Upgrade base image to m91

[rosbo]

http://b/227193319

[rosbo]

Dropping ml_metrics. This is an old package created by Ben Hamner. Last updated in 2015. Fails to install at build time now:

#17 58.62 Collecting ml_metrics
#17 58.64   Downloading ml_metrics-0.1.4.tar.gz (5.0 kB)
#17 58.65   Preparing metadata (setup.py): started
#17 59.04   Preparing metadata (setup.py): finished with status 'error'
#17 59.05   error: subprocess-exited-with-error
#17 59.05   
#17 59.05   × python setup.py egg_info did not run successfully.
#17 59.05   │ exit code: 1
#17 59.05   ╰─> [1 lines of output]
#17 59.05       error in ml_metrics setup command: use_2to3 is invalid.
#17 59.05       [end of output]
#17 59.05   
#17 59.05   note: This error originates from a subprocess, and is likely not a problem with pip.
#17 59.05 error: metadata-generation-failed
#17 59.05 
#17 59.05 × Encountered error while generating package metadata.
#17 59.05 ╰─> See above for output.

Also, it was already failing at import time.

In our Python image currently released:

import ml_metrics

Fails with:

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
/tmp/ipykernel_34/1657033094.py in <module>
----> 1 import ml_metrics

/opt/conda/lib/python3.7/site-packages/ml_metrics/__init__.py in <module>
----> 1 from quadratic_weighted_kappa import *
      2 from elementwise import *
      3 from auc import auc
      4 from average_precision import apk, mapk

ModuleNotFoundError: No module named 'quadratic_weighted_kappa'

[Philmod]

LGTM if build successful.