Force version of sklearn in examples

[damccorm]

Force sklearn version to the same version the models were trained on. This ensures that the examples will pass correctly.

Fixes#25967

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[damccorm]

Run Python 3.9 PostCommit

[codecov]

Codecov Report

Merging #25968 (27d611a) into master (3a1b641) will decrease coverage by 0.01%.
The diff coverage is 33.33%.

@@ Coverage Diff @@## master #25968 +/- ##
==========================================
- Coverage 71.42% 71.41% -0.01% 
==========================================
Files 779 779 Lines 102530 102536 +6 ==========================================
- Hits 73228 73226 -2 - Misses 27842 27850 +8 
Partials 1460 1460 

Flag	Coverage Δ
python	79.95% <33.33%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...s/inference/sklearn_japanese_housing_regression.py	32.83% <33.33%> (+0.02%)	⬆️
...examples/inference/sklearn_mnist_classification.py	43.13% <33.33%> (-0.62%)	⬇️

... and 4 files with indirect coverage changes

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[tvalentyn]

will dependabot update this file?

[damccorm]

I'm not sure - I added a comment so that it will be obvious we should reject PRs that try to bump this.

[tvalentyn]

Please fix lint & yapf and run an integration test suite that runs the example.

[damccorm]

Please fix lint & yapf and run an integration test suite that runs the example.

Whoops, missed the linting failures - thanks.

Python3.9 postcommit does run the example, so that's already done. I'll run it again though.

[damccorm]

Run Python 3.9 PostCommit