This versioning scheme is consistent with other
tools in the python ecosystem so it feels more natural
and allows better interaction with other tools.
fixes#346
`pypyX.Y.exe` executables are missing from PyPy archives on Windows before v7.3.9 (X.Y < 3.9)
`pypy2.7` symlinks are also missing from macOS/Linux PyPy archives before v7.3.9
relates to #346
* test for pypy new version notation
* formatting
* uncommented condition
* test
* added pypy to test matrix
* test
* test
* restored all tests
* removed logs, added multiarch support for toolcache
* reduced test matrix
* removed extra condition about arch