Bump numpy from 1.17.1 to 1.22.0 in /backend

Bumps [numpy](https://github.com/numpy/numpy) from 1.17.1 to 1.22.0.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/HOWTO_RELEASE.rst)
- [Commits](numpy/numpy@v1.17.1...v1.22.0)

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

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

Author: dependabot[bot]

backend/requirements.txt

@@ -21,7 +21,7 @@ kiwisolver==1.1.0
 MarkupSafe==1.1.1
 matplotlib==3.0.3
 nltk==3.4.5
-numpy==1.17.1
+numpy==1.22.0
 oauthlib==3.1.0
 openapi-codec==1.3.2
 packaging==20.3