Small CONTRIBUTING.md command line change

Instead of just doing `argocd version`, be a little more explicit
by passing in the server name and insecure flag.  This will make
sure that you're doing the version of the instance you're
port-forwarding above, as opposed to some other argocd.

While this works as is, I noted that before I ran the
`argocd login` command, I didn't have a default config with the
server name and insecure flag.  So the first time I did this,
the `argocd version` command gave an error:

FATA[0000] Argo CD server address unspecified

CONTRIBUTING.md

@@ -32,7 +32,7 @@ kubectl port-forward service/argo-cd-argocd-server -n argocd 8080:443
 In a new terminal:
 
 ```
-argocd version
+argocd version --server localhost:8080 --insecure
 # reset password to 'Password1!'
 kubectl -n argocd patch secret argocd-secret \
   -p '{"stringData": {