Add proper copyright notices to all source files with accurate date
ranges per contributor based on git history. Add contributors to
composer.json authors and README.
- Rename package to gecka/roundcube-ident_switch
- Change license from GPL-3.0+ to AGPL-3.0+
- Bump PHP requirement to >= 8.1
- Bump roundcube/plugin-installer to >= 0.3.0
- Set Roundcube min-version to 1.6
- Update homepage and support URLs to GitHub
- Update composer repository URL to HTTPS