feat: add project versions (#110)

* refactor: allow version matrixes by projects

* feat: add initial version-matrix for mage-os

* feat: add project as optional input to action

* docs: document new input

* refactor: tighten types a bit

* chore: apply change requests from code review

supported-version/src/project/validate-projects.spec.ts

@@ -0,0 +1,12 @@
+import { validateProject } from "./validate-projects";
+
+describe('validateProject', () => {
+    it('returns `true` if its a valid project', () => {
+        expect(validateProject("magento-open-source")).toBe(true);
+        expect(validateProject("mage-os")).toBe(true);
+    });
+    
+    it('throws a helpful exception if it is an invalid project', () => {
+        expect(() => validateProject(<any>"quark")).toThrowError();
+    })
+})