fstring wip
Run pyupgrade
fix broken pyupgrade fstring
run pyupgrade on plugin dir
fixup! remove py2 remnants and use mocks in tests
small print bugfix
The file=sys.stderr was part of the format(), so an error got printed to
stdout
Drop use of codecs package
Use builtins.open() instead
fixup! remove py2 remnants and use mocks in tests
[GH-632] raising exception in upgrade.py on fail
Handling it in install.py to prevent config from being overwritten when upgrade fails
[GH-632] removing unnecessary whitespace
[GH-632] removing unreachable return statement
[GH-632] adding call to action to report issue when upgrade fails
