fix: Support Netcore 6.0 (#10634)

Author: Blackclaws

docs/generators/csharp-netcore.md

@@ -31,7 +31,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |returnICollection|Return ICollection<T> instead of the concrete type.| |false|
 |sortParamsByRequiredFlag|Sort method arguments to place required parameters before optional parameters.| |true|
 |sourceFolder|source folder for generated code| |src|
-|targetFramework|The target .NET framework version. To target multiple frameworks, use `;` as the separator, e.g. `netstandard2.1;netcoreapp3.0`|<dl><dt>**netstandard1.3**</dt><dd>.NET Standard 1.3 compatible</dd><dt>**netstandard1.4**</dt><dd>.NET Standard 1.4 compatible</dd><dt>**netstandard1.5**</dt><dd>.NET Standard 1.5 compatible</dd><dt>**netstandard1.6**</dt><dd>.NET Standard 1.6 compatible</dd><dt>**netstandard2.0**</dt><dd>.NET Standard 2.0 compatible</dd><dt>**netstandard2.1**</dt><dd>.NET Standard 2.1 compatible</dd><dt>**netcoreapp2.0**</dt><dd>.NET Core 2.0 compatible</dd><dt>**netcoreapp2.1**</dt><dd>.NET Core 2.1 compatible</dd><dt>**netcoreapp3.0**</dt><dd>.NET Core 3.0 compatible</dd><dt>**netcoreapp3.1**</dt><dd>.NET Core 3.1 compatible</dd><dt>**net47**</dt><dd>.NET Framework 4.7 compatible</dd><dt>**net5.0**</dt><dd>.NET 5.0 compatible</dd></dl>|netstandard2.0|
+|targetFramework|The target .NET framework version. To target multiple frameworks, use `;` as the separator, e.g. `netstandard2.1;netcoreapp3.0`|<dl><dt>**netstandard1.3**</dt><dd>.NET Standard 1.3 compatible</dd><dt>**netstandard1.4**</dt><dd>.NET Standard 1.4 compatible</dd><dt>**netstandard1.5**</dt><dd>.NET Standard 1.5 compatible</dd><dt>**netstandard1.6**</dt><dd>.NET Standard 1.6 compatible</dd><dt>**netstandard2.0**</dt><dd>.NET Standard 2.0 compatible</dd><dt>**netstandard2.1**</dt><dd>.NET Standard 2.1 compatible</dd><dt>**netcoreapp2.0**</dt><dd>.NET Core 2.0 compatible</dd><dt>**netcoreapp2.1**</dt><dd>.NET Core 2.1 compatible</dd><dt>**netcoreapp3.0**</dt><dd>.NET Core 3.0 compatible</dd><dt>**netcoreapp3.1**</dt><dd>.NET Core 3.1 compatible</dd><dt>**net47**</dt><dd>.NET Framework 4.7 compatible</dd><dt>**net5.0**</dt><dd>.NET 5.0 compatible</dd><dt>**net6.0**</dt><dd>.NET 6.0 compatible</dd></dl>|netstandard2.0|
 |useCollection|Deserialize array types to Collection&lt;T&gt; instead of List&lt;T&gt;.| |false|
 |useDateTimeOffset|Use DateTimeOffset to model date-time properties| |false|
 |useOneOfDiscriminatorLookup|Use the discriminator's mapping in oneOf to speed up the model lookup. IMPORTANT: Validation (e.g. one and only one match in oneOf's schemas) will be skipped.| |false|

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java

@@ -70,7 +70,8 @@ public class CSharpNetCoreClientCodegen extends AbstractCSharpCodegen {
             FrameworkStrategy.NETCOREAPP_3_0,
             FrameworkStrategy.NETCOREAPP_3_1,
             FrameworkStrategy.NETFRAMEWORK_4_7,
-            FrameworkStrategy.NET_5_0
+            FrameworkStrategy.NET_5_0,
+            FrameworkStrategy.NET_6_0
     );
     private static FrameworkStrategy defaultFramework = FrameworkStrategy.NETSTANDARD_2_0;
     protected final Map<String, String> frameworks;
@@ -1001,6 +1002,8 @@ private static abstract class FrameworkStrategy {
         };
         static FrameworkStrategy NET_5_0 = new FrameworkStrategy("net5.0", ".NET 5.0 compatible", "net5.0", Boolean.FALSE) {
         };
+        static FrameworkStrategy NET_6_0 = new FrameworkStrategy("net6.0", ".NET 6.0 compatible", "net6.0", Boolean.FALSE) {
+        };
         protected String name;
         protected String description;
         protected String testTargetFramework;