demonstrate using github actions to release a dynamic lib

This is useful for building a dynamically-linked lib used by Godot Engine, e.g. in delta-pack.

Shows configuration for win, mac, linux x86_64.

Take a look at the github actions config.

After you make some changes that you want published, you need to push tags to your repo:

git tag -a v0.1.0 -m "my release"
git push --tags

Here are the github actions that we rely on for this configuration:

• rust-toolchain action
• softprops gh-action-release

Thanks also to Alican for the write-up giving an example of multi-platform configuration!