Updated HelpWriter to explain /overrideConfig usage.

Author: labmonkey42

src/GitVersionExe/ArgumentParser.cs

@@ -293,7 +293,7 @@ public static Arguments ParseArguments(List<string> commandLineArguments)
 
                         switch (configOverride[0])
                         {
-                            case "tagPrefix":
+                            case "tag-prefix":
                                 if (1 < configOverride.Length)
                                 {
                                     arguments.OverrideConfig.TagPrefix = configOverride[1];

src/GitVersionExe/HelpWriter.cs

@@ -25,6 +25,7 @@ path            The directory containing .git. If not defined current directory
                     eg /output json /showvariable SemVer - will output `1.2.3+beta.4`
     /l              Path to logfile.
     /showconfig     Outputs the effective GitVersion config (defaults + custom from GitVersion.yaml) in yaml format
+    /overrideConfig Overrides GitVersion config values inline (semicolon-separated key value pairs e.g. /overrideConfig:tag-prefix=Foo)
 
     # AssemblyInfo updating
     /updateassemblyinfo