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

Bumps [numpy](https://github.com/numpy/numpy) from 1.19.3 to 1.19.4.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/master/doc/HOWTO_RELEASE.rst.txt)
- [Commits](numpy/numpy@v1.19.3...v1.19.4)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

python/requirements/CI-complete/requirements.txt

@@ -10,7 +10,7 @@ msgpack==1.0.0
 msprime==0.7.4
 networkx==2.5
 newick==1.0.0
-numpy==1.19.3
+numpy==1.19.4
 portion==2.1.3
 pyparsing==2.4.7
 pysam==0.16.0.1