Various memory and file descriptor leaks in apt-python

Various memory and file descriptor leaks were found in apt-python files python/arfile.cc, python/tag.cc, python/tarfile.cc, aka GHSL-2020-170. This issue affects: python-apt 1.1.0~beta1 versions prior to 1.1.0~beta1ubuntu0.16.04.10; 1.6.5ubuntu0 versions prior to 1.6.5ubuntu0.4; 2.0.0ubuntu0 versions prior to 2.0.0ubuntu0.20.04.2; 2.1.3ubuntu1 versions prior to 2.1.3ubuntu1.1;