Adding all-features CI test (#87)

.github/workflows/main.yml

@@ -74,6 +74,12 @@ jobs:
           command: test
           args: --no-default-features ${{ matrix.frontend_feature }},std ${{ matrix.backend_feature }}
 
+      - name: Run cargo test with all features enabled
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --all-features
+
   build-no-std:
     name: Build with no-std on ${{ matrix.target }}
     runs-on: ubuntu-latest