Bump NNCF version to 2.19.0 (#3630)

### Reason for changes

Branch for 2.18.0 was created

### Related tickets

172462

Author: AlexanderDokuchaev

src/nncf/version.py

@@ -9,7 +9,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "2.18.0"
+__version__ = "2.19.0"
 
 
 BKC_TORCH_SPEC = "==2.8.*"