[test] use assertIn where appropriate
Automatically generated with:
find -name unittest_*.py -o -name test_*.py | xargs sed -i -e 's/assertTrue(\([^,]*\) in \([^,]*\))/assertIn(\1, \2)/'
usr/lib/PY_VERSION/*-packages/cubicweb/server/
usr/lib/PY_VERSION/*-packages/cubicweb/hooks/
usr/lib/PY_VERSION/*-packages/cubicweb/sobjects/
usr/lib/PY_VERSION/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/