LegacyAPIWarning: The Query.get() method is considered legacy

[FrostyX]

We have probably hundreds of warnigns like this in the test suite:

tests/test_logic/test_builds_logic.py::TestBuildsLogic::test_package_assigned_to_build_initially
  /home/jkadlcik/git/copr/frontend/coprs_frontend/tests/test_logic/test_builds_logic.py:473: LegacyAPIWarning: The Query.get() method is considered legacy as of the 1.x series of SQLAlchemy and becomes a legacy construct in 2.0. The metho
d is now available as Session.get() (deprecated since: 2.0) (Background on SQLAlchemy 2.0 at: https://sqlalche.me/e/b8d9)