Merge pull request #1804 from tskit-dev/dependabot/pip/requirements/CI-complete/codecov-2.1.12

Bump codecov from 2.1.10 to 2.1.12 in /requirements/CI-complete

Author: mergify[bot]

requirements/CI-complete/requirements.txt

@@ -1,5 +1,5 @@
 bintrees==2.2.0
-codecov==2.1.10
+codecov==2.1.12
 daiquiri==3.0.0
 demes==0.1.2
 hypothesis==6.14.5