Add awesome-lint as a github action

this will catch:
- dead links
- duplicate links
- inconsistent formatting
- etc

of which there are a bunch to clean up at the moment.

... and basically help this list look consistent with
the other awesome lists on the internet.

any rules can be disabled if they are wrong or annoying.
it doesn't block the repo from being updated in anyway, though
that can be configured.

.github/workflows/main.yml

@@ -0,0 +1,12 @@
+name: CI
+on:
+  pull_request:
+    branches: [main]
+jobs:
+  Awesome_Lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - run: npx awesome-lint