update electron branch

[spaceunifyfifty]

The electron branch that these docs say to clone is out of date. Running sbt build throws errors the following error

[info] [launcher] getting org.scala-sbt sbt 1.3.10  (this may take some time)...
[info] [launcher] getting Scala 2.12.10 (for sbt)...
error:
  bad constant pool index: 0 at pos: 49176
     while compiling: <no file>
        during phase: globalPhase=<no phase>, enteringPhase=<some phase>
     library version: version 2.12.10
    compiler version: version 2.12.10
  reconstructed args: -classpath /Users/john/.sbt/boot/scala-2.12.10/lib/scala-library.jar -Yrangepos

  last tree to typer: EmptyTree
       tree position: <unknown>
            tree tpe: <notype>
              symbol: null
           call site: <none> in <none>

== Source file context for tree position ==

Exception in thread "sbt-parser-init-thread" java.lang.ExceptionInInitializerError
        at sbt.internal.parser.SbtParserInit$$anon$2.run(SbtParser.scala:171)
Caused by: scala.reflect.internal.FatalError: 
  bad constant pool index: 0 at pos: 49176
     while compiling: <no file>
        during phase: globalPhase=<no phase>, enteringPhase=<some phase>
     library version: version 2.12.10
    compiler version: version 2.12.10
  reconstructed args: -classpath /Users/john/.sbt/boot/scala-2.12.10/lib/scala-library.jar -Yrangepos

  last tree to typer: EmptyTree
       tree position: <unknown>
            tree tpe: <notype>
              symbol: null
           call site: <none> in <none>

== Source file context for tree position ==


        at scala.reflect.internal.Reporting.abort(Reporting.scala:68)
        at scala.reflect.internal.Reporting.abort$(Reporting.scala:64)
        at scala.reflect.internal.SymbolTable.abort(SymbolTable.scala:28)
        at scala.tools.nsc.symtab.classfile.ClassfileParser$ConstantPool.errorBadIndex(ClassfileParser.scala:384)
        at scala.tools.nsc.symtab.classfile.ClassfileParser$ConstantPool.getExternalName(ClassfileParser.scala:248)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.readParamNames$1(ClassfileParser.scala:838)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.parseAttribute$1(ClassfileParser.scala:844)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.$anonfun$parseAttributes$7(ClassfileParser.scala:911)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.parseAttributes(ClassfileParser.scala:911)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.parseMethod(ClassfileParser.scala:620)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.$anonfun$parseClass$4(ClassfileParser.scala:533)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.parseClass(ClassfileParser.scala:533)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.$anonfun$parse$2(ClassfileParser.scala:161)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.$anonfun$parse$1(ClassfileParser.scala:146)
        at scala.tools.nsc.symtab.classfile.ClassfileParser.parse(ClassfileParser.scala:129)
        at scala.tools.nsc.symtab.SymbolLoaders$ClassfileLoader.doComplete(SymbolLoaders.scala:329)
        at scala.tools.nsc.symtab.SymbolLoaders$SymbolLoader.complete(SymbolLoaders.scala:230)
        at scala.reflect.internal.Symbols$Symbol.info(Symbols.scala:1542)
        at scala.reflect.internal.Definitions.scala$reflect$internal$Definitions$$enterNewMethod(Definitions.scala:50)
        at scala.reflect.internal.Definitions$DefinitionsClass.String_$plus$lzycompute(Definitions.scala:1128)
        at scala.reflect.internal.Definitions$DefinitionsClass.String_$plus(Definitions.scala:1128)
        at scala.reflect.internal.Definitions$DefinitionsClass.syntheticCoreMethods$lzycompute(Definitions.scala:1414)
        at scala.reflect.internal.Definitions$DefinitionsClass.syntheticCoreMethods(Definitions.scala:1396)
        at scala.reflect.internal.Definitions$DefinitionsClass.symbolsNotPresentInBytecode$lzycompute(Definitions.scala:1426)
        at scala.reflect.internal.Definitions$DefinitionsClass.symbolsNotPresentInBytecode(Definitions.scala:1426)
        at scala.reflect.internal.Definitions$DefinitionsClass.init(Definitions.scala:1482)
        at scala.tools.nsc.Global$Run.<init>(Global.scala:1199)
        at sbt.internal.parser.SbtParser$.<init>(SbtParser.scala:121)
        at sbt.internal.parser.SbtParser$.<clinit>(SbtParser.scala)
        ... 1 more
java.lang.UnsupportedOperationException: The Security Manager is deprecated and will be removed in a future release
        at java.base/java.lang.System.setSecurityManager(System.java:431)
        at sbt.TrapExit$.installManager(TrapExit.scala:53)
        at sbt.StandardMain$.runManaged(Main.scala:127)
        at sbt.xMain$.run(Main.scala:67)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at sbt.internal.XMainConfiguration.run(XMainConfiguration.scala:45)
        at sbt.xMain.run(Main.scala:39)
        at xsbt.boot.Launch$.$anonfun$run$1(Launch.scala:149)
        at xsbt.boot.Launch$.withContextLoader(Launch.scala:176)
        at xsbt.boot.Launch$.run(Launch.scala:149)
        at xsbt.boot.Launch$.$anonfun$apply$1(Launch.scala:44)
        at xsbt.boot.Launch$.launch(Launch.scala:159)
        at xsbt.boot.Launch$.apply(Launch.scala:44)
        at xsbt.boot.Launch$.apply(Launch.scala:21)
        at xsbt.boot.Boot$.runImpl(Boot.scala:78)
        at xsbt.boot.Boot$.run(Boot.scala:73)
        at xsbt.boot.Boot$.main(Boot.scala:21)
        at xsbt.boot.Boot.main(Boot.scala)
[error] [launcher] error during sbt launcher: java.lang.UnsupportedOperationException: The Security Manager is deprecated and will be removed in a future release

Please update the branch for future users using latest versions of scala3/sbt. Thanks!