ci: update dist-tag to make flags optional.

We can't guarantee that the user provided these options at compile time, so all options should include `undefined` in their types. This makes the type system a little smarter and hopefully prevent future mistakes. Fortunately we were already doing the right thing, this will make sure we continue to do so in the future.

I opted to use `Partial<DistTagArgs>` so that all future flags would be implicitly forced to be optional. Otherwise, we may forget to make them optional and potentially introduce a bug.

Author: dgp1130

scripts/dist-tag.ts

@@ -37,7 +37,7 @@ interface DistTagOptions {
 /**
  * This function adds a tag to all public packages in the CLI repo.
  */
-export default function(args: DistTagOptions, logger: logging.Logger) {
+export default function(args: Partial<DistTagOptions>, logger: logging.Logger) {
   if (args.help) {
     logger.info(`dist-tag adds a tag to all public packages in the CLI repo.