fix: fix copyright check script

[scottdover]

Summary
This updates our copyright check script to run on all valid files, instead of those added in a recent commit. You can run this check manually via npm run copyright:check. This is also ran via github actions.

Additionally, this adds a fix flag (npm run copyright:check --fix) that will automatically prepend copyright information to files that are missing it.

Testing

• Make sure github actions fails build (on first commit)
• Make sure github actions passed on next build (after running --fix)
• Make sure copyright appears on files

[smorrisj]

Looks great. Thanks for doing this. I was wondering why my new files for the sas 9 local changes didnt error out the PR check. Will fix those after this merges

[scnwwu]

Great! Thanks!

[scnwwu]

typo for correct

[Becky-Williamson]

Scott walked me though the changes for copyright-check and demonstrated how the build will fail if the copyright information is not included in the file. They then demoed the copyright check fix and rebuilt successfully when it was completed.