Add workflow to the list of default OAuth scopes we request

Since GitHub CLI now offers to authenticate your Git as well, the token
we request here will be used for git pushes. Since we do anticipate our
users making edits to their GitHub Actions workflow files, we want them
to be able to push their changes, and this scope allows that.

internal/authflow/flow.go

@@ -63,7 +63,7 @@ func authFlow(oauthHost string, IO *iostreams.IOStreams, notice string, addition
 		verboseStream = w
 	}
 
-	minimumScopes := []string{"repo", "read:org", "gist"}
+	minimumScopes := []string{"repo", "read:org", "gist", "workflow"}
 	scopes := append(minimumScopes, additionalScopes...)
 
 	flow := &auth.OAuthFlow{