.github: add Coverage workflow

A part of #429.

Signed-off-by: Anna Shaleva <[email protected]>

.github/workflows/go.yml

@@ -34,6 +34,34 @@ jobs:
     - name: Test
       run: go test -v ./...
 
+  cover:
+    name: Coverage
+    runs-on: ubuntu-22.04
+
+    env:
+      CGO_ENABLED: 0
+      GOEXPERIMENT: nocoverageredesign
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.23'
+          cache: true
+
+      - name: Write coverage profile
+        run: go test -v ./... -coverprofile=./coverage.txt -coverpkg=./contracts/...
+
+      - name: Upload coverage results to Codecov
+        uses: codecov/codecov-action@v4
+        with:
+          fail_ci_if_error: true # if something is wrong on uploading codecov results, then this job will fail
+          files: ./coverage.txt
+          slug: nspcc-dev/neofs-contract
+          token: ${{ secrets.CODECOV_TOKEN }}
+          verbose: true
+
   build:
     name: Build contracts and RPC bindings
     runs-on: ubuntu-latest