v0.4.4

<!-- Release notes generated using configuration in .github/release.yml at v0.4.4 -->

What's Changed

• docs: add signal enums to machine types by @dangra in https://github.com/superfly/fly-go/pull/218
• docs: add SIGUSR2 to machine signal enums by @dangra in https://github.com/superfly/fly-go/pull/219

Full Changelog: https://github.com/superfly/fly-go/compare/v0.4.3...v0.4.4