Merge pull request #601 from tskit-dev/dependabot/pip/requirements/CI-tests-pip/numpy-1.21.4

Bump numpy from 1.21.3 to 1.21.4 in /requirements/CI-tests-pip

Author: mergify[bot]

requirements/CI-tests-pip/requirements.txt

@@ -3,7 +3,7 @@ colorama==0.4.4
 daiquiri==3.0.1
 humanize==3.12.0
 matplotlib==3.4.3
-numpy==1.21.3
+numpy==1.21.4
 pandas==1.2.5
 pytest==6.2.5
 pytest-xdist==2.4.0