Bump numpy from 1.21.3 to 1.21.4 (#35)

Bumps [numpy](https://github.com/numpy/numpy) from 1.21.3 to 1.21.4.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/HOWTO_RELEASE.rst.txt)
- [Commits](numpy/numpy@v1.21.3...v1.21.4)

---
updated-dependencies:
- dependency-name: numpy
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/tutorials-requirements.txt

@@ -1,4 +1,4 @@
 matplotlib==3.4.3
 pandas==1.3.4
-numpy==1.21.3
+numpy==1.21.4
 seaborn==0.11.2

requirements.txt

@@ -1,3 +1,3 @@
-numpy==1.21.3
+numpy==1.21.4
 pandas==1.3.4
 nbval==0.9.6