fix: Adding gh actions

.github/workflows/ci.yaml

@@ -0,0 +1,20 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request: {}
+
+jobs:
+  test:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: bazelbuild/setup-bazelisk@v1
+      - name: Mount bazel cache
+        uses: actions/cache@v2
+        with:
+          path: "~/.cache/bazel"
+          key: bazel
+      - run: bazel test //...