Add support for coverage. (#550)

.github/workflows/coverage.yml

@@ -0,0 +1,38 @@
+name: coverage
+on: [push]
+jobs:
+
+  build:
+    name: build
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+    steps:
+
+    - name: Set up Go
+      uses: actions/setup-go@v3
+      with:
+        go-version: 1.18
+      id: go
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v3
+
+    - name: Get dependencies
+      run: go get -v -t -d ./...
+
+    - name: Build
+      run: go build -v .
+
+    - name: Test
+      run: go test -coverpkg="github.com/gdamore/v2/..." -covermode=count -coverprofile="coverage.txt" ./...
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v3.1.0
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
+        file: ./coverage.txt
+        flags: unittests
+        name: codecov-umbrella
+        yml: ./codecov.yml