Initial release process document

[igaray]

Release process documentation

Description

• Add RELEASE.md
• Update pull request template to include an action item to update the changelog. This is now part of documentation process and PR acceptance criteria.
• Update CHANGELOG.md to bring it back up to date.

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated.

[codecov]

Codecov Report

Merging #959 (a85a935) into main (a1a65fd) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #959   +/-   ##
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  Coverage   97.74%   97.74%           
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  Files          74       74           
  Lines       30392    30392           
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  Hits        29708    29708           
  Misses        684      684           

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[igamigo]

Probably not very useful (especially because it doesn't totally apply to releases), but here are some points that might be worth considering for the PR template:

• Verified that related documentation/references are still valid (eg, if the project structure changes and a readme is moved, are references from the documentation in starknet-in-rust still valid?). We might want to communicate these changes to pertinent teams.
• If dependencies are introduced/removed in a release, there might be some things that might have to be double checked (eg, is it no_std? is it cross-platform?). These are probably more related to the integration pipelines though.