lang/python37: Update to 3.7.12

Changelog:

https://docs.python.org/release/3.7.12/whatsnew/changelog.html#changelog

PR: 258519
Reported by: Mike Fisher
Approved by: kai (python, maintainer)
MFH: 2021Q3
Security: 0e561173-0fa9-11ec-a2fa-080027948c12