Bump tensorflow from 2.6.4 to 2.7.2 in /hackathons/hdfc_hackathon

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.6.4 to 2.7.2.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.6.4...v2.7.2)

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

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

Author: dependabot[bot]

hackathons/hdfc_hackathon/requirements.txt

@@ -1,4 +1,4 @@
-tensorflow==2.6.4
+tensorflow==2.7.2
 #tensorflow-gpu==2.0.0-rc1
 imblearn
 catboost