replace travis CI with github actions (check syntax, check links)

- travis CI free plans were discontinued
- CI pipeline is similar to https://github.com/awesome-selfhosted/awesome-selfhosted-data and uses https://github.com/nodiscc/hecat
- the pipeline will not pass until https://github.com/awesome-foss/awesome-sysadmin/issues/416 has been fixed
- ref. https://github.com/awesome-foss/awesome-sysadmin/issues/405

.github/workflows/ci.yml

@@ -0,0 +1,19 @@
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - run: make import
+      - run: make awesome_lint
+      - run: make url_check