Added required Ubuntu dependencies to testing flow

.github/workflows/testing.yml

@@ -29,6 +29,12 @@ jobs:
       - name: Install Rust stable
         uses: dtolnay/rust-toolchain@stable
 
+      - name: Install dependencies (Ubuntu only)
+        if: matrix.platform == 'ubuntu-20.04'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libdbus-1-dev pkg-config
+
       - name: Run test suite
         working-directory: ./
         run: cargo test