update side bar

[skzhang1]

Why are these changes needed?

Show all the blog posts on the website

Related issue number

Closes #687

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 ✅

Comparison is base (f939dda) 29.05% compared to head (d5226f7) 29.05%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #702   +/-   ##
=======================================
  Coverage   29.05%   29.05%           
=======================================
  Files          27       27           
  Lines        3407     3407           
  Branches      767      767           
=======================================
  Hits          990      990           
  Misses       2345     2345           
  Partials       72       72           

Flag	Coverage Δ
unittests	28.99% <ø> (ø)

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