Bump numpy from 1.16.2 to 1.21.0 in /scripts

Bumps [numpy](https://github.com/numpy/numpy) from 1.16.2 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@v1.16.2...v1.21.0)

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

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

Author: dependabot[bot]

scripts/requirements.txt

@@ -1,6 +1,6 @@
 pytube==9.6.0
 Keras==2.2.4
-numpy==1.16.2
+numpy==1.21.0
 tensorflow==1.14.0
 opencv_contrib_python==3.4.2.17
 Pillow==7.0.0