feat: add changelog action and conventional commits

[julia-rabello]

Adding an automatic changelog based on this RFC.

Commit rules:

Commit type	When to use	Allowed scopes
new	Add new API file, endpoint, or parameters.	api, endpoint, parameter
fix	Fix typos, broken links, or minor corrections. Adding a scope is optional (e.g. fix(broken-link): learn more, fix: marketplace name).	typo, broken-link, markdown
update	Update existing descriptions, endpoints, or fields.	N/A
remove	Remove deprecated APIs, endpoints, or fields.	N/A
docs	Update repository documentation files (README.md).	N/A
test	Internal testing changes (hidden from changelog).	N/A
feat	New features and actions within the repository.	N/A
chore	Apply routine changes or maintenance tasks that don't modify API reference content (e.g. chore: update postman files).	N/A

[github-actions]

Thanks for your contribution. The .json file will be checked now with Spectral.