chore(version): fix dev version to a large number

GitOrigin-RevId: 9567513c1f75dd9504d3faf12d6dd2034d668c4a

imperative/python/megengine/version.py

@@ -6,5 +6,5 @@
 # Unless required by applicable law or agreed to in writing,
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-__version__ = "0.8.0"
+__version__ = "1.2.0.dev"