add codecov integration

.github/workflows/push.yml

@@ -23,9 +23,13 @@ jobs:
     - uses: actions/setup-go@v1
       with:
         go-version: 1.14
-    - run: go test -cover ./...
+    - run: go test -cover -coverprofile=coverage.txt -covermode=atomic ./...
       env:
-        CGO_ENABLED: 0
+          CGO_ENABLED: 0
+    - uses: codecov/codecov-action@v1
+      with:
+        files: coverage.txt
+        fail_ci_if_error: true # optional (default = false)
 
   snapshot:
     name: Snapshot

.gitignore

@@ -17,3 +17,5 @@
 *.nupkg
 .vscode/
 .idea/
+
+coverage.txt