fix(deps): add packaging requirement (#154)

Author: busunkim96

setup.py

@@ -28,7 +28,11 @@
 # 'Development Status :: 4 - Beta'
 # 'Development Status :: 5 - Production/Stable'
 release_status = "Development Status :: 5 - Production/Stable"
-dependencies = ["google-api-core[grpc] >= 1.22.2, < 2.0.0dev", "proto-plus >= 1.10.0"]
+dependencies = [
+    "google-api-core[grpc] >= 1.22.2, < 2.0.0dev",
+    "proto-plus >= 1.10.0",
+    "packaging >= 14.3",
+]
 extras = {"libcst": "libcst >= 0.2.5"}
 scripts = ["scripts/fixup_keywords.py"]
 

testing/constraints-3.6.txt

@@ -8,3 +8,5 @@
 google-api-core==1.22.2
 proto-plus==1.10.0
 libcst==0.2.5
+packaging==14.3
+google-auth==1.24.0  # TODO: remove when google-auth>=1.25.0 is transitively required through google-api-core