Chore: add a CLA checking action (#1292)

* Chore: add a CLA checking action

* Rm myself to test

* Refs

* PR trigger

* Tweak the if

* Restore myself

.github/workflows/cla.yml

@@ -0,0 +1,23 @@
+name: 'CLA Assistant'
+
+on:
+  issue_comment:
+
+  pull_request:
+
+jobs:
+  CLAssistant:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'CLA Assistant'
+        if: github.event_name == 'pull_request' || github.event.comment.body == 'I have read the CLA Document and I hereby sign the CLA' || github.event.comment.body == 'recheckcla'
+        uses: gnosis/github-action@master
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          path-to-signatures: 'signatures/version1/cla.json'
+          path-to-cla-document: 'https://safe.global/cla/'
+          branch: 'cla-signatures'
+          allowlist: lukasschor,mikheevm,rmeissner,germartinez,Uxio0,dasanra,francovenica,tschubotz,luarx,bot*,katspaugh,DaniSomoza,iamacook,yagopv,usame-algan,schmanu,DiogoSoaress,JagoFigueroa
+          empty-commit-flag: false
+          blockchain-storage-flag: false