bump main version into v3.1 (#1974)

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

Author: chensuyue

neural_compressor/version.py

@@ -15,4 +15,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Intel® Neural Compressor: An open-source Python library supporting popular model compression techniques."""
-__version__ = "3.0"
+__version__ = "3.1"