Update the file with Python public keys.

Generated the keys file using these commands:

gpg --recv-keys 6A45C816 36580288 7D9DC8D2 18ADD4FF A4135B38 A74B06BF EA5BBD71 ED9D77D5 E6DF025C 6F5E1540 F73C700D
gpg --armor --export 6A45C816 36580288 7D9DC8D2 18ADD4FF A4135B38 A74B06BF EA5BBD71 ED9D77D5 E6DF025C 6F5E1540 F73C700D > python-pubkeys.txt

The list of key IDs was copied from this page:
https://www.python.org/download