Add support for Linux with glibc (#61)

* Conditionally import Glibc on Linux for fcntl calls

* Extract transport implementations into separate files

* Fix warning in test

* Add ubuntu-latest to CI test matrix

* Switch to vapor/swiftly-action for setup step

* Configure Prettier extension to format GitHub Actions workflows

* Setup with different actions depending on platform

* Rename step

* Rename job

* Update README

.vscode/settings.json

@@ -4,5 +4,8 @@
 	"editor.codeActionsOnSave": {
 		"source.fixAll": "explicit",
 		"source.organizeImports": "explicit"
+	},
+	"[github-actions-workflow]": {
+		"editor.defaultFormatter": "esbenp.prettier-vscode"
 	}
 }