Bump numpy from 1.16.2 to 1.18.5 in /cvat/requirements (#1722)

Bumps [numpy](https://github.com/numpy/numpy) from 1.16.2 to 1.18.5.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/master/doc/HOWTO_RELEASE.rst.txt)
- [Commits](https://github.com/numpy/numpy/compare/v1.16.2...v1.18.5)

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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

cvat/requirements/base.txt

@@ -7,7 +7,7 @@ django-compressor==2.4
 django-rq==2.0.0
 EasyProcess==0.2.3
 Pillow==7.1.2
-numpy==1.16.2
+numpy==1.18.5
 python-ldap==3.2.0
 pytz==2018.3
 pyunpack==0.1.2