Add GitHub workflow which verifies that `dist/index.js` is up to date

[Marcono1234]

Problem

It seems currently there is no GitHub workflow which verifies that dist/index.js is up to date, this is problematic because:

• it could lead to a stale version of the action being released by accident
• a malicious user could try to inject additional code in dist/index.js, and hope that it is overlooked during pull request review

Related:

• dist/index.js is not up-to-date #92
• ncc output differs #169

Potential solution

Could you please either uncomment this step in the main.yml workflow again:

action-gh-release/.github/workflows/main.yml

Lines 26 to 32 in 5be0e66

	# - name: "check for uncommitted changes"
	# # Ensure no changes, but ignore node_modules dir since dev/fresh ci deps installed.
	# run: |
	# git diff --exit-code --stat -- . ':!node_modules' \
	# || (echo "##[error] found changed files after build. please 'npm run build && npm run fmt'" \
	# "and check in all changes" \
	# && exit 1)

(I think that should work as check to verify that dist/index.js is up to date)

Or use a dedicated workflow, for example https://github.com/actions/typescript-action/blob/main/.github/workflows/check-dist.yml (with build steps adjusted), and remove the commented-out step from main.yml mentioned above.