enable coveralls

enable coveralls via github actions

.github/workflows/cover.yml

@@ -0,0 +1,23 @@
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+name: Coverage
+jobs:
+  coverage:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: '1.14.x'
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Test
+        run: |
+          go test -coverprofile=profile.cov ./...
+      - name: Send coverage
+        uses: shogo82148/actions-goveralls@v1
+        with:
+          path-to-profile: profile.cov