Initial release of github2mr.

This is the initial release which is fully-functional and works
for myself, self-hosted github enterprise installations, and
privately hosted gitbucket installs.

It has not been tested against other systems (gogs, gitea, etc),
but reports of success/failure or patches would be most welcome.

.github/workflows/pull_request.yml

@@ -0,0 +1,10 @@
+on: pull_request
+name: Pull Request
+jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+    - name: Test
+      uses: skx/github-action-tester@master