[Feature] proposal events

[yun-yeo]

Summary of changes

• Update SDK version to v0.37.7
• Append treasury proposal events

Report of required housekeeping

• Github issue OR spec proposal link
• Wrote tests
• Updated relevant documentation (docs/)
• Added a relevant changelog entry: clog add [section] [stanza] [message]

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(FOR ADMIN) Before merging

• Added appropriate labels to PR
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)
• Confirm added tests are consistent with the intended behavior of changes
• Ensure all tests pass

[codecov]

Codecov Report

Merging #324 into develop will increase coverage by 0.08%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop     #324      +/-   ##
===========================================
+ Coverage    72.87%   72.95%   +0.08%     
===========================================
  Files           73       73              
  Lines         3089     3099      +10     
===========================================
+ Hits          2251     2261      +10     
  Misses         731      731              
  Partials       107      107