Port rpmwatcher to python3

[ydirson]

No description provided.

[stormi]

It fails when it needs to run a script from within a CentOS 7.5 container:

+ docker run --rm -t --privileged --network host -v /home/rpmwatcher/data:/data -v /home/rpmwatcher/git/xcp/scripts/rpmwatcher:/scripts centos:7.5.1804 /scripts/rpmwatcher_extract_deps.py 8.3 /data
/bin/env: python3: No such file or directory

[ydirson]

Maybe it is time to add python3 to the default build env, with a goal of getting rid of python2 ASAP (maybe even right now)?

[stormi]

I don't know if it changes much to the build env. The container here is a basic centos 7.5 container (to which local XCP-ng repos are then added). It resembles xcp-ng-build-env but it's not it.