Bump graphene from 2.1.3 to 2.1.5 (#5028)

Bumps [graphene](https://github.com/graphql-python/graphene) from 2.1.3 to 2.1.5.
- [Release notes](https://github.com/graphql-python/graphene/releases)
- [Commits](https://github.com/graphql-python/graphene/compare/v2.1.3...v2.1.5)

requirements/common.txt

@@ -236,9 +236,9 @@ graphene-django==2.2.0 \
     --hash=sha256:760a18068feb5457e2ec00d2447c09b2fbac2a6b8c32cc8be2abce3752107ad3
 
 # Used by graphene-django
-graphene==2.1.3 \
-    --hash=sha256:faa26573b598b22ffd274e2fd7a4c52efa405dcca96e01a62239482246248aa3 \
-    --hash=sha256:b8ec446d17fa68721636eaad3d6adc1a378cb6323e219814c8f98c9928fc9642
+graphene==2.1.5 \
+    --hash=sha256:6d6a68c7b3b40325bf9af8a3dca22639f5a57eededf4449c1db198d7eb117af7 \
+    --hash=sha256:8eee7e2ae9c22d01cf85a43f8c1aeb776a478bc2e20e0ca8d5fb17ba4b9f4767
 graphql-core==2.1 \
     --hash=sha256:9462e22e32c7f03b667373ec0a84d95fba10e8ce2ead08f29fbddc63b671b0c1 \
     --hash=sha256:889e869be5574d02af77baf1f30b5db9ca2959f1c9f5be7b2863ead5a3ec6181