Bump numpy from 1.11.2 to 1.21.0

Bumps [numpy](https://github.com/numpy/numpy) from 1.11.2 to 1.21.0.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/HOWTO_RELEASE.rst)
- [Commits](numpy/numpy@v1.11.2...v1.21.0)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
 Flask==0.11.1
-numpy==1.11.2
+numpy==1.21.0
 sympy==1.1