Add timm version check

[guarin]

Changes

• Add version check for timm
• Only import AIM model parts if timm >= 0.9.9

This fixes import issues if users have an older version of timm installed. For details see:

• https://github.com/microsoft/torchgeo/issues/1824
• https://github.com/lightly-ai/lightly/pull/1479#issuecomment-1909750194

[guarin]

FYI @adamjstewart. Would this fix the problem in torchgeo?

[codecov[bot]]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (25894a9) 84.40% compared to head (7b458e8) 84.40%.

Files	Patch %	Lines
lightly/utils/dependency.py	75.00%	4 Missing :warning:
lightly/models/utils.py	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1487 +/- ## ========================================== - Coverage 84.40% 84.40% -0.01% ========================================== Files 139 140 +1 Lines 5777 5783 +6 ========================================== + Hits 4876 4881 +5 - Misses 901 902 +1 ```

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[adamjstewart]

Packaging is no longer needed now right?

[guarin]

Packaging is no longer needed now right?

Yes exactly :) Plus we actually verify whether the required classes are there instead of relying on the version.

The change should also speed up importing lightly in environments where torchvision and/or timm are installed as we now only import them when needed.

[adamjstewart]

Thanks for the quick fix @guarin, glad we'll be able to use future timm versions again!