Previously, it was necessary to support older versions of Python for
compatibility. F-strings were released in Python 3.6. Python 3.5 was
marked as unsupported by the end of 2020, so now it's possible to start
using f-strings safely for better readability and performance.
Added "go" availability check before trying to build an application.
update_action() method used were possible and fixed bug with
the relative path determination in test_static_chroot.py.
Templates optimization and style fixes.
