Add docstring for common module (#1905)

Signed-off-by: yiliu30 <[email protected]>

Author: yiliu30

neural_compressor/common/__init__.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""The common module."""
 
 from neural_compressor.common.utils import (
     level,