Fixed some small things:
f339a1b Bump lxml from 4.7.1 to 4.9.1 (#59)
c92a545 small tweaks (#58)
894b503 fix: matching shebangs for all files (#54)
2707c71 rpi4 support tested, update tests (#51)
127a49d change in-repo project name to RPi.GPIO2 (#50)
f8caa5f Makefile: fix typo (#48)
0e761de Add CNAME for custom docs domain; gitignore latex byproducts (#46)
47d6ae5 Add HTML rendering of spec (#45)
7af7bc0 Documentation edits - Section 4.1 (#44)
3f47744 Persistent GPIO permissions (#43)