Convert `release-branches.py` and `update-required-checks.sh` to TypeScript #3137

Job	Run time
Upload debug artifacts (stable-v2.20.3)	5m 59s
Upload debug artifacts (nightly-latest)	5m 56s
Upload debug artifacts (default)	5m 53s
Upload debug artifacts (linked)	5m 38s
Download and check debug artifacts	5s
	23m 31s

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