Bump C# version to 12.0 (#1287)

.editorconfig

@@ -173,7 +173,7 @@ dotnet_diagnostic.IDE0026.severity = none
 dotnet_diagnostic.IDE0026WithoutSuggestion.severity = none
 dotnet_diagnostic.IDE0027.severity = none
 dotnet_diagnostic.IDE0027WithoutSuggestion.severity = none
-dotnet_diagnostic.IDE0028.severity = suggestion
+dotnet_diagnostic.IDE0028.severity = none # Collection initialization can be simplified
 dotnet_diagnostic.IDE0029.severity = suggestion
 dotnet_diagnostic.IDE0031.severity = suggestion
 dotnet_diagnostic.IDE0033.severity = suggestion
@@ -198,6 +198,11 @@ dotnet_diagnostic.IDE0079.severity = none
 dotnet_diagnostic.IDE0090.severity = none
 dotnet_diagnostic.IDE0220.severity = none
 dotnet_diagnostic.IDE0270.severity = silent
+dotnet_diagnostic.IDE0290.severity = none # Use primary constructor
+dotnet_diagnostic.IDE0300.severity = none # Use collection expression
+dotnet_diagnostic.IDE0301.severity = none # ImmutableArray<object>.Empty -> []
+dotnet_diagnostic.IDE0303.severity = none # ImmutableArray.Create(x) -> [x]
+dotnet_diagnostic.IDE0305.severity = none # x.ToArray() -> [.. x]
 dotnet_diagnostic.IDE1005.severity = suggestion
 dotnet_diagnostic.IDE1006.severity = suggestion
 
@@ -210,3 +215,5 @@ dotnet_diagnostic.CA1826.severity = none
 dotnet_diagnostic.CA1860.severity = none
 dotnet_diagnostic.CA1861.severity = none
 dotnet_diagnostic.CA2231.severity = none
+
+dotnet_diagnostic.SYSLIB1045.severity = silent # Use 'GeneratedRegexAttribute' to generate the regular expression implementation at compile-time.

src/Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 
  <PropertyGroup>
- <LangVersion>10.0</LangVersion>
+ <LangVersion>12.0</LangVersion>
  <SignAssembly>true</SignAssembly>
  <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)Roslynator.snk</AssemblyOriginatorKeyFile>
  <Authors>Josef Pihrt</Authors>