always use HEAD for gh action

Author: mfleming

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     steps:
       - name: Hello world action step
         id: hello
-        uses: nyrkio/nyrkio-gh-action@v0.2
+        uses: nyrkio/nyrkio-gh-action@main
         with:
           who-to-greet: "Mona the Octocat"
       # Use the output from the `hello` step