Add daily testing with GitHub Actions

Author: nmemoto

.github/workflows/daily-testing.yml

@@ -0,0 +1,18 @@
+name: daily-testing
+on:
+  schedule:
+    - cron: '0 0 * * *'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v4
+        with:
+          go-version-file: './go.mod'
+          cache-dependency-path: './go.sum'
+      - name: Run test
+        run: |
+          go test github.com/nmemoto/gh-trending/...