Change scm version scheme to support 2.1.0.devx (#940)

Signed-off-by: XuanYang-cn <[email protected]>

setup.py

@@ -1,7 +1,5 @@
 import pathlib
 import setuptools
-from datetime import datetime
-import re
 
 HERE = pathlib.Path(__file__).parent
 
@@ -12,7 +10,7 @@
     author='Milvus Team',
     author_email='[email protected]',
     setup_requires=['setuptools_scm'],
-    use_scm_version={'local_scheme': 'no-local-version'},
+    use_scm_version={'local_scheme': 'no-local-version', 'version_scheme': 'release-branch-semver'},
     description="Python Sdk for Milvus",
     long_description=README,
     long_description_content_type='text/markdown',