Update the Helm version docs

Have just updated the helm version docs to include the GoVersion field.

Signed-off-by: Thomas O'Donnell <andy.tom@gmail.com>

cmd/helm/version.go

@@ -33,12 +33,13 @@ Show the version for Helm.
 This will print a representation the version of Helm.
 The output will look something like this:
 
-version.BuildInfo{Version:"v2.0.0", GitCommit:"ff52399e51bb880526e9cd0ed8386f6433b74da1", GitTreeState:"clean"}
+version.BuildInfo{Version:"v3.2.1", GitCommit:"fe51cd1e31e6a202cba7dead9552a6d418ded79a", GitTreeState:"clean", GoVersion:"go1.13.10"}
 
 - Version is the semantic version of the release.
 - GitCommit is the SHA for the commit that this version was built from.
 - GitTreeState is "clean" if there are no local code changes when this binary was
   built, and "dirty" if the binary was built from locally modified code.
+- GoVersion is the version of Go that was used to compile Helm.
 
 When using the --template flag the following properties are available to use in
 the template: