Merge pull request #1063 from tskit-dev/dependabot/pip/python/requirements/CI-tests-pip/numpy-1.19.4

Bump numpy from 1.19.3 to 1.19.4 in /python/requirements/CI-tests-pip

Author: mergify[bot]

python/requirements/CI-tests-pip/requirements.txt

@@ -1,4 +1,4 @@
-numpy==1.19.3
+numpy==1.19.4
 pytest==6.1.2
 pytest-xdist==2.1.0
 jsonschema==3.2.0