Remove cargo-tarpaulin due to instability

See discussion at georust#676

.github/workflows/test.yml

@@ -16,7 +16,6 @@ jobs:
       - geo
       - geo_postgis
       - geo_fuzz
-      - coverage
       - bench
     steps:
       - name: Mark the job as a success
@@ -98,23 +97,6 @@ jobs:
         uses: actions/checkout@v2
       - run: cargo build --bins
 
-  coverage:
-    name: coverage
-    runs-on: ubuntu-latest
-    if: "!contains(github.event.head_commit.message, '[skip ci]') && !contains(github.event.head_commit.message, '[skip coverage]')"
-    container:
-      image: georust/geo-ci
-      options: --security-opt seccomp=unconfined
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v2
-      - name: Generate code coverage
-        run: cargo tarpaulin --verbose --all-features --workspace --timeout 120 --out Lcov
-      - name: Upload coverage to Coveralls
-        uses: coverallsapp/github-action@v1.1.1
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          path-to-lcov: lcov.info
   bench:
     name: bench
     runs-on: ubuntu-latest
@@ -125,4 +107,3 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
       - run: cargo bench --no-run
-