refactor(changelog): simplify logic for get_oldest_and_newest_rev#1539

bearomorphism wants to merge 2 commits intocommitizen-tools:v4-9-0-testcommitizen-tools/commitizen:v4-9-0-testfrom

bearomorphism:get_oldest_and_newest_revbearomorphism/commitizen:get_oldest_and_newest_revCopy head branch name to clipboard