html.py must run with either Python 2 or 3 to support COPR builds

html.py must run with either Python 2 or 3 to support COPR builds

The script starts with `#!/usr/bin/env python3` but COPR builds run it as
`/usr/bin/python2 "./html.py"`. In the long term we should phase out Python
2 and make sure Python 3 is used everywhere.  In the short term, let's
repair COPR builds first, then plan the Python 2 to 3 transition.

This reverts e83b646f.

Signed-off-by: Dimitri Papadopoulos <3350651-DimitriPapadopoulos@users.noreply.gitlab.com>
Signed-off-by: Daniel Lenski <dlenski@gmail.com>