Bump numpy from 1.18.2 to 1.21.0

Bumps [numpy](https://github.com/numpy/numpy) from 1.18.2 to 1.21.0.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/HOWTO_RELEASE.rst.txt)
- [Commits](numpy/numpy@v1.18.2...v1.21.0)

---
updated-dependencies:
- dependency-name: numpy
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 sympy==1.5.1
-numpy==1.18.2
+numpy==1.21.0
 setuptools==46.1.3
 matplotlib==3.2.1
 scipy==1.4.1