Attempt to fix coverage by copying Zebra workflow

.github/workflows/coverage.yaml

@@ -1,6 +1,7 @@
-name: CI
+name: Coverage
 
 on:
+  workflow_dispatch:
   pull_request:
     branches:
       - main
@@ -11,11 +12,13 @@ on:
 jobs:
 
   coverage:
-    name: Coverage
+    name: Coverage (+nightly)
     timeout-minutes: 30
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2.3.4
+      - uses: actions/checkout@v2.4.0
+        with:
+          persist-credentials: false
 
       - uses: actions-rs/toolchain@v1.0.7
         with:
@@ -24,35 +27,13 @@ jobs:
           profile: minimal
           components: llvm-tools-preview
 
-      - name: Install rustfilt symbol demangler
-        run: |
-          cargo install rustfilt
+      - name: Install cargo-llvm-cov cargo command
+        run: cargo install cargo-llvm-cov
 
-      - name: Rerun tests for coverage
+      - name: Generate code coverage
         env:
-          RUSTFLAGS: -Zinstrument-coverage -C link-dead-code -C debuginfo=2
-          LLVM_PROFILE_FILE: "${{ github.workspace }}/test.%p.profraw"
-          ZEBRA_SKIP_NETWORK_TESTS: 1
-        run: |
-          cargo test
-          cargo test --no-run --message-format=json | jq -r "select(.profile.test == true) | .filenames[]" | grep -v dSYM - > filenames.txt
-
-      - name: Merge coverage data
-        run: |
-          $(rustc --print target-libdir)/../bin/llvm-profdata merge test.*.profraw -o test.profdata
-
-      - name: Generate detailed html coverage report for github artifact
-        run: |
-          $(rustc --print target-libdir)/../bin/llvm-cov show -format=html -ignore-filename-regex=".*/.cargo/registry/.*" -ignore-filename-regex=".*/.cargo/git/.*" -ignore-filename-regex=".*/.rustup/.*" -Xdemangler=rustfilt -show-instantiations -output-dir=./coverage -instr-profile=./test.profdata $(printf -- "-object %s " $(cat filenames.txt))
-
-      - uses: actions/upload-artifact@v2
-        with:
-          name: coverage
-          path: ./coverage
-
-      - name: Generate lcov coverage report for codecov
-        run: |
-          $(rustc --print target-libdir)/../bin/llvm-cov export -format=lcov -instr-profile=test.profdata $(printf -- "-object %s " $(cat filenames.txt)) > "lcov.info"
+          CARGO_INCREMENTAL: 0
+        run: cargo llvm-cov --lcov > lcov.info
 
       - name: Upload coverage report to Codecov
-        uses: codecov/codecov-action@v1.5.2
+        uses: codecov/codecov-action@v2.1.0