This commit changes the current way of testing + prebuilding native
addons on Githugb Actions by introducing the following changes:

* Separate the test workflow (run on any push) from the prebuilding
  workflow (run only on new tags).

* Use prebuildify-cross to compile native addons for two architectures
  (x64, arm64) and for two different libc implementations (glibc, musl)
  on Linux.

* Upgrade to v3 of the checkout and setup-node actions.

* Prebuild the native addon and test on x64 Windows too.

* Use compiler defaults for C++ version on MacOS.