GitHub CI: Test the unnamed-tmpfile on Linux explicitly

.github/workflows/ci.yml

@@ -9,13 +9,16 @@ env:
 
 jobs:
   cargo-test-linux:
-    name: Build and Test (Linux${{ contains(matrix.target, 'musl') && ', musl' || '' }})
+    name: Build and Test (Linux${{ contains(matrix.target, 'musl') && ', musl' || '' }}${{ matrix.features != 'default' && format(', {0}', matrix.features) || '' }})
     runs-on: ubuntu-latest
     strategy:
       matrix:
         target:
           - x86_64-unknown-linux-gnu
           - x86_64-unknown-linux-musl
+        features:
+          - default
+          - unnamed-tmpfile
     steps:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
@@ -25,7 +28,7 @@ jobs:
       - name: Build and Test
         run: |
           export TEST_DIR=$RUNNER_TEMP
-          cargo test --target ${{ matrix.target }} --release --verbose
+          cargo test --target ${{ matrix.target }} --features ${{ matrix.features }} --release --verbose
       - name: Lint
         run: |
           cargo clippy --all-targets