Bump tensorflow from 2.3.1 to 2.4.2

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.3.1 to 2.4.2.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.3.1...v2.4.2)

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

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

Author: dependabot[bot]

requirements.txt

@@ -2,6 +2,6 @@ cython>=0.29
 numpy==1.16.4
 easydict>=1.9,<=1.10
 opencv-python>=3.4,<3.5
-tensorflow==2.3.1
+tensorflow==2.4.2
 tensorlayer==2.2.3
 pycocotools==2.0.0  # must be installed after cython and numpy are installed

setup.py

@@ -12,7 +12,7 @@
         "numpy==1.16.4",
         "easydict>=1.9,<=1.10",
         "opencv-python>=3.4,<3.5",
-        "tensorflow==2.3.1",
+        "tensorflow==2.4.2",
         "tensorlayer==2.2.3",
         "pycocotools"
     ],