Bump numpy from 1.19.1 to 1.21.0 in /freegbdt

Bumps [numpy](https://github.com/numpy/numpy) from 1.19.1 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@v1.19.1...v1.21.0)

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

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

Author: dependabot[bot]

freegbdt/requirements.txt

@@ -10,7 +10,7 @@ idna==2.10
 jmespath==0.10.0
 joblib==0.16.0
 lightgbm==2.3.1
-numpy==1.19.1
+numpy==1.21.0
 packaging==20.4
 pandas==1.0.1
 pyparsing==2.4.7