Update github workflow to install coverage with toml support.

  - Also update CONTRIBUTING.md.

Author: Diptorup Deb

.github/workflows/generate-coverage.yaml

@@ -79,7 +79,7 @@ jobs:
       - name: Install dpctl dependencies
         shell: bash -l {0}
         run: |
-          pip install numpy cython setuptools pytest pytest-cov coverage
+          pip install numpy cython setuptools pytest pytest-cov coverage[toml]
 
       - name: Build dpctl with coverage
         shell: bash -l {0}

CONTRIBUTING.md

@@ -154,6 +154,10 @@ these steps:
     To generate the coverage data for dpctl's Python sources, you only need to
     install `coverage`.
 
+    ```bash
+    python -m pip install coverage[toml]
+    ```
+
 3. Build dpctl with code coverage support.
 
     ```bash