Add grcov workflow

.github/grcov.yml

@@ -0,0 +1,5 @@
+ignore-not-existing: true
+branch: true
+output-type: html
+binary-path: ./target/debug/
+output-path: ./target/debug/coverage/

.github/workflows/grcov.yaml

@@ -0,0 +1,74 @@
+name: Code coverage
+
+env:
+  RUST_BACKTRACE: 1
+  CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
+
+on:
+  workflow_dispatch:
+  workflow_run:
+    workflows: [Tests]
+    types: [completed]
+    branches: [main]
+
+jobs:
+  on-success:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    steps:
+      - uses: actions/checkout@v1
+      - id: cache-rustup
+        name: Cache Rust toolchain
+        uses: actions/cache@v3
+        with:
+          path: ~/.rustup
+          key: toolchain-grcov
+      - id: cache-cargo
+        name: Cache Cargo
+        uses: actions/cache@v3
+        with:
+          path: ~/.cargo
+          key: cargo-grcov
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --all --all-features --no-fail-fast
+        env:
+          CARGO_INCREMENTAL: '0'
+          RUSTFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+          RUSTDOCFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+      - uses: actions-rs/grcov@v0.1
+        with:
+          config: .github/grcov.yml
+      - name: Copy artifacts
+        run: |
+          mkdir -p "_site"
+          cp -r target/debug/coverage _site/
+      - name: Upload report
+        uses: actions/upload-pages-artifact@v1
+    deploy:
+      # Add a dependency to the build job
+      needs: on-success
+
+      # Grant GITHUB_TOKEN the permissions required to make a Pages deployment
+      permissions:
+        pages: write      # to deploy to Pages
+        id-token: write   # to verify the deployment originates from an appropriate source
+
+      # Deploy to the github-pages environment
+      environment:
+        name: github-pages
+        url: ${{ steps.deployment.outputs.page_url }}
+
+      # Specify runner + deployment step
+      runs-on: ubuntu-latest
+      steps:
+        - name: Deploy to GitHub Pages
+          id: deployment
+          uses: actions/deploy-pages@v2 # or the latest "vX.X.X" version tag for this action
+
+