Bump package version to v1.9.1

Author: jzebedee

src/LibDeflate/LibDeflate.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>net6.0;net5.0;netcoreapp3.1;netstandard2.1;netstandard2.0</TargetFrameworks>
     <AssemblyName>LibDeflate.NET</AssemblyName>
-    <VersionPrefix>1.8.1</VersionPrefix>
+    <VersionPrefix>1.9.1</VersionPrefix>
     <Authors>jzebedee</Authors>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PackageProjectUrl>https://github.com/jzebedee/LibDeflate</PackageProjectUrl>