Add continuous integration workflow configuration

This commit introduces a new continuous integration workflow via GitHub actions. This workflow runs on every push event, checking out the current code, setting up the 'buf' CLI, and pushes the module to the BSR, all under an Ubuntu environment.

.github/workflows/ci.yaml

@@ -0,0 +1,15 @@
+on: push # Apply to all push
+jobs:
+  push-module:
+    runs-on: ubuntu-latest
+    steps:
+      # Run `git checkout`
+      - uses: actions/checkout@v2
+      # Install the `buf` CLI
+      - uses: bufbuild/buf-setup-action@v1
+      # Push module to the BSR
+      - uses: bufbuild/buf-push-action@v1
+        with:
+          buf_token: ${{ secrets.BUF_TOKEN }}
+          create_visibility: private
+          draft: ${{ github.ref_name != 'main'}}