Add CLA check GitHub action (#6479)

.github/workflows/main.yml

@@ -0,0 +1,16 @@
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  cla-checker:
+    runs-on: ubuntu-latest
+    name: "Check CLA"
+    steps:
+      - name: "Lookup PR Author"
+        uses: influxdata/clasee@v1
+        with:
+          spreadsheet: "1jnRZYSw83oa6hcEBb1lxK6nNvXrWnOzPT8Bz9iR4Q8s"
+          range: "Form Responses!E:E"
+        env:
+          CLASEE_SECRET: ${{ secrets.CLASEE_SECRET }}