template for updating all existing instances to the next Nextcloud major version

This template extends https://github.com/nextcloud/all-in-one/issues/180

Tasks

TODO:

• Wait for at least Nextcloud $NEXT_NC_MAJOR_VERSION.0.1
• report to Tobi if release is delayed compared to NCE (and post in sysadmin issue if one exists)

Issues:

• https://github.com/nextcloud/server/issues?q=is%3Aopen%20is%3Aissue%20label%3A$NEXT_NC_MAJOR_VERSION-feedback%20label%3Ahigh
• https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue++label%3A$NEXT_NC_MAJOR_VERSION-feedback+

Apps not compatible:

• increase aio version to Nextcloud $NEXT_NC_MAJOR_VERSION
• other bundled apps
• further apps: https://help.nextcloud.com/t/app-support-for-nc-$NEXT_NC_MAJOR_VERSION/ (successor of https://help.nextcloud.com/t/apps-with-missing-support-for-nc-34/244733)

Test:

• check if all included features work
  • ClamAV
  • Collabora
  • OnlyOffice (deprecated)
  • EuroOffice
  • Fulltextsearch
  • Imaginary (for previews of heic, heif, illustrator, pdf, svg, tiff and webp.
  • Talk
  • talk recording
  • docker-socket-proxy (deprecated)
  • HARP
  • whiteboard
• check admin overview
• check each other overview
• check if nextcloud-aio app works
• add other issues/features that should get in for the major release
• increase docker API_VERSION ? (check latest beta or stable release logs of docker)
• remove notice for update to next major version from aio interface
• ...