Bump tensorflow from 2.11.1 to 2.12.1 in /firmware/micro_mnist/scripts

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.11.1 to 2.12.1.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.11.1...v2.12.1)

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

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

Author: dependabot[bot]

firmware/micro_mnist/scripts/requirements.txt

@@ -1,2 +1,2 @@
-tensorflow==2.11.1
+tensorflow==2.12.1
 numpy==1.21.0