Verify merge as git action

.github/workflows/verify-merge.yml

@@ -0,0 +1,12 @@
+name: ci/gh-actions/verify-merge
+
+on: [push, pull_request]
+
+jobs:
+  verify-merge:
+    runs-on: ubuntu-20.04
+    steps:
+    - uses: actions/checkout@v1
+    - name: verify-merge
+      run: python3 ./verify-merge.py --import-keys
+

.travis.yml

@@ -1,7 +0,0 @@
-language: python
-
-python:
-  - "3.7.0"
-
-script:
-  - python ./verify-merge.py --import-keys