Prepare 8.0.0

[julien-nc]

Added

• Add pronouns and birthdate mapping, factorize simple mapping attributes handling when provisioning @julien-nc #1102
• Add optional provider-specific post_logout_uri setting, pass it as a GET param to the end_session_endpoint @julien-nc #1120
• Add support for Nextcloud 33
• Allow setting the default token endpoint auth method in config.php (if token_endpoint_auth_methods_supported is not set in the discovery payload) @julien-nc #1199

Changed

• Adjust testing matrix for Nextcloud 32 on main @nickvergessen #1196
• Drop support for Nextcloud 28, remove deprecated IConfig::setAppValue usages @julien-nc #1200
• ⚠️ Use client_secret_basic as token endpoint auth by default, use client_secret_post if supported @julien-nc #1199