python3: bump version to 3.9.7

python3: bump version to 3.9.7

Refreshed patches.
And apply hack for line-endings in pep517 (from pip).

Hack comment:
  # FIXME: [1] get rid of this asap; 'patch' doesn't like Windows endings, and this file is full of them...
  #        I actually tried this in a number of ways and the only way to fix this is to implement
  #        a poor-man's dos2unix using sed.
  #        The issue is with the pip package; it seems that it throws in some Windows line-endings
  #        and 'patch' won't handle them. So, we do a "dos2unix" and then patch.
  #        We can get rid of this once this is solved upstream and in pip:
  #            https://github.com/pypa/pep517/pull/130

Signed-off-by: Alexandru Ardelean <redacted>