Fix issue with git checkout main

[ekzhu]

Why are these changes needed?

When git clone the repo from the main branch, got errors:

Encountered 3 files that should have been pointers, but weren't:
	website/blog/2024-03-03-AutoGen-Update/img/dalle_gpt4v.png
	website/blog/2024-03-03-AutoGen-Update/img/gaia.png
	website/blog/2024-03-03-AutoGen-Update/img/teach.png

To fix, update website/blog/2024-03-03-AutoGen-Update/img/.gitattributes to include all images in the directory.

Related issue number

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 36.02%. Comparing base (09a4918) to head (0506aaa).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1876   +/-   ##
=======================================
  Coverage   36.02%   36.02%           
=======================================
  Files          63       63           
  Lines        6621     6621           
  Branches     1462     1462           
=======================================
  Hits         2385     2385           
  Misses       4041     4041           
  Partials      195      195           

Flag	Coverage Δ
unittests	36.02% <ø> (ø)

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[qingyun-wu]

Just wondering why there are also changes in the figures?

[ekzhu]

Just wondering why there are also changes in the figures?

I think some metadata in the images might have been changed. But the images themselves are not changed.

E.g., https://github.com/ekzhu/autogen/blob/fix-checkout/website/blog/2024-03-03-AutoGen-Update/img/dalle_gpt4v.png

(Some files a bit large..., we might want to shrink them)