Fix some r# errors

Author: JakeGinnivan

src/GitVersionCore.Tests/IntegrationTests/DocumentationSamples.cs

@@ -1,6 +1,5 @@
 using GitTools;
 using GitTools.Testing;
-using GitVersion;
 using GitVersionCore.Tests;
 using NUnit.Framework;
 using Shouldly;

src/GitVersionExe/ArgumentParser.cs

@@ -299,8 +299,6 @@ public static Arguments ParseArguments(List<string> commandLineArguments)
                                     arguments.OverrideConfig.TagPrefix = configOverride[1];
                                 }
                                 break;
-                            default:
-                                break;
                         }
                     }