Add code coverage reporting

Author: Donovan Dall

.github/workflows/coverage.yml

@@ -0,0 +1,50 @@
+name: Test-and-upload-coverage
+
+on:
+  pull_request:
+    branches: [ master ]
+
+jobs:
+
+  cancel:
+    name: Cancel Previous Runs
+    runs-on: ubuntu-latest
+    steps:
+      - name: cancel running workflows
+        uses: everphone-gmbh/cancel-previous-workflows@v5
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
+
+  coverage:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        redis-version: [4, 5]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Cache cargo bin
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          override: true
+      - name: Run cargo-tarpaulin
+        uses: actions-rs/[email protected]
+        with:
+          args: '-t 640'
+          out-type: Lcov
+      - uses: romeovs/[email protected]
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          lcov-file: ./lcov.info
+      - name: Archive code coverage results
+        uses: actions/upload-artifact@v1
+        with:
+          name: code-coverage-report
+          path: lcov.info