fix(deps): add packaging requirement (#293)

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

@@ -21,7 +21,11 @@
 description = "Client library for the Dialogflow API"
 version = "2.1.2"
 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",
+]
 
 package_root = os.path.abspath(os.path.dirname(__file__))
 

testing/constraints-3.6.txt

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