Fix python postcommit dependency workflow

[akashorabek]

Issue #30799
Successful run example: https://github.com/akashorabek/beam/actions/runs/12926316024

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[akashorabek]

R: @damccorm

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[damccorm]

had one comment, the rest looks good though

[damccorm]

Do you know what the underlying issue is with these dependencies? It would be better to keep one of these as a lower bound if possible so that we are able to test that beam is still compatible with lower versions of transformers. My ideal would be to have 2 tests, one that is testPy39transformers-428 to test our lower bound and one that is testPy39transformers-447 to test our upper bound

[akashorabek]

@damccorm The tests testPy39transformers-428, 429, 430 were using the latest version of sentence-transformers (3.4.0), which doesn't support these transformers versions. As a result, it pulled the latest transformers 4.48.1, which no longer supports older torch (<2.0.0) versions that we were using, causing the tests to fail.
So I kept tests for:

• transformers 4.28.x (with sentence-transformers 2.2.2, the latest version that supports 4.28)
• transformers 4.47.x (the last version that still supports older torch)
• transformers 4.48.x (the latest overall version, uses upgraded torch).

[damccorm]

Thanks!