Create action for CI on pull request

.github/workflows/pull_request.yml

@@ -0,0 +1,25 @@
+on: pull_request
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.13, 1.14, 1.15]
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - run: go get -t ./...
+
+      - name: Test
+        run: go test -coverprofile=coverage.txt -covermode=atomic
+
+      - name: Upload coverage to codecov
+        uses: codecov/codecov-action@v1