packaging: mark as developer version

--HG--
branch : stable
8 jobs for topic/stable/release-prep in 6 minutes and 35 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
passed checks-py2 #160690

00:02:35

passed checks-py3 #160691

00:00:55

passed doc #160696

00:00:36

manual pytype #160689
allowed to fail manual
passed tests-py2-cext #160692

00:06:34

passed tests-py2-pure #160693

00:02:41

passed tests-py3-cext #160694

00:04:30

passed tests-py3-pure #160695

00:06:23