fix(deps): add packaging requirement (#46)

Add packaging requirement. packaging.version is used for a version comparison in transports/base.py and is needed after the upgrade to gapic-generator-python 0.46.3

Author: busunkim96

setup.py

@@ -43,6 +43,7 @@
  install_requires=(
  "google-api-core[grpc] >= 1.22.2, < 2.0.0dev",
  "proto-plus >= 1.10.0",
+ "packaging >= 14.3",
  ),
  python_requires=">=3.6",
  classifiers=[

testing/constraints-3.6.txt

@@ -7,3 +7,4 @@
 # Then this file should have foo==1.14.0
 google-api-core==1.22.2
 proto-plus==1.10.0
+packaging==14.3