Prepare Objects release 3.6.0

[stevenbal]

• Resolve release blockers
  • ♻️ [#564] Remove linkableToZaken field from objecttype mode #724
• Upgrade open-api-framework to latest version
• Check security tab and upgrade packages to fix vulnerabilities
• Check translations
• Bump API version number (if applicable)
  • Version bump
  • Regenerate API spec
  • Update READMEs with release dates + links
• Bump version number with bin/bump-my-version.sh bump <major|minor|patch>
• Update changelog
• Check the impact of this release on the Helm charts and make issues for this in https://github.com/maykinmedia/charts if needed, e.g.
  • New environment variables were added
  • New setup configuration steps or changes to format
  • New containers required
  • ...

[stevenbal]

@Floris272 do you know if all the necessary changes to make the migration to local objecttypes possible are in master? Does #713 only contain changes that are needed for the next major release?