MR Process: updateDependencies should check if working copy is clean

[zepumph]

While doing an MR for https://github.com/phetsims/phet-io-wrappers/issues/519, I accidentally had some working copy changes in perennial-alias instead of perennial for maintenance code. In this case, updateDependencies really failed in a gross way. It got partially through pushing changes and the internal maintenance json state was really messed up. @jonathanolson can we please do a double check here? Similar to how we do it for dev versions:

perennial/js/grunt/dev.js

Lines 71 to 79 in 2977b62

	const dependencies = await getDependencyRepos( repo );
	for ( let i = 0; i < dependencies.length; i++ ) {
	const dependency = dependencies[ i ];
	const isClean = await gitIsClean( dependency );
	if ( !isClean ) {
	throw new Error( `Unclean status in ${dependency}, cannot deploy` );
	}
	}