Bump tensorflow from 1.11.0 to 2.5.1 in /examples/visual_nav_cmp

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 1.11.0 to 2.5.1.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v1.11.0...v2.5.1)

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

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

Author: dependabot[bot]

examples/visual_nav_cmp/requirements.txt

@@ -2,4 +2,4 @@ numpy>=1.16.0
 opencv-python==4.0.0.21
 recordclass==0.10.2
 yacs==0.1.6
-tensorflow==1.11.0
+tensorflow==2.5.1