Add upgrade workflow

[james-toussaint]

• End goal is to be able to trigger the upgrade job though the UI:
  
• For the moment, the job must be manually trigger through command line until this workflow is available on main default branch:
  gh workflow run .github/workflows/upgrade.yml --ref feature/upgrade-workflow -f network=hardhat
• The upgrade can be performed on 2 environments (networks):
  • hardhat: For testing purposed only. See successful deployment here ✔️
  • bellecour
• Files changed during upgrade are automatically committed. See:
  • An example here
  • And what happens if some files are changes during upgrade or see commit history from a test PR
• Some useful resources:
  • https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#workflow_dispatch
  • https://github.com/orgs/community/discussions/25219#discussioncomment-10902997
  • Running a GitHub Actions workflow that doesn't exist yet on the default branch

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.30%. Comparing base (543948e) to head (b3fa2c3).
Report is 15 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop      #64   +/-   ##
========================================
  Coverage    99.30%   99.30%           
========================================
  Files            4        4           
  Lines          287      287           
  Branches        34       53   +19     
========================================
  Hits           285      285           
  Misses           2        2           

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