Bump kombu from 4.5.0 to 4.6.0 (#5017)

Bumps [kombu](https://kombu.readthedocs.io) from 4.5.0 to 4.6.0.

requirements/common.txt

@@ -45,7 +45,7 @@ Django==2.2.1 \
 
 celery==4.3.0 --hash=sha256:528e56767ae7e43a16cfef24ee1062491f5754368d38fcfffa861cdb9ef219be --hash=sha256:4c4532aa683f170f40bd76f928b70bc06ff171a959e06e71bf35f2f9d6031ef9
 
-kombu==4.5.0 --hash=sha256:7b92303af381ef02fad6899fd5f5a9a96031d781356cd8e505fa54ae5ddee181 --hash=sha256:389ba09e03b15b55b1a7371a441c894fd8121d174f5583bbbca032b9ea8c9edd
+kombu==4.6.0 --hash=sha256:14997e6d76d36f2b296f57e37fd1d388e4e0159edea8368a8c6f4620a355a722 --hash=sha256:27345bb569eb6bb583bca27dfc0ef181ca6c59c40c6e203cecaa0aeca84360be
 
 simplejson==3.16.0 \
     --hash=sha256:6c3258ffff58712818a233b9737fe4be943d306c40cf63d14ddc82ba563f483a \