Update license headers

AUTHORS

apps/dav/lib/CalDAV/CalDavBackend.php

apps/dav/lib/CardDAV/CardDavBackend.php

apps/dav/lib/Command/MoveCalendar.php

apps/dav/lib/DAV/Sharing/Backend.php

apps/dav/lib/Migration/BuildSocialSearchIndex.php

...dav/lib/Migration/BuildSocialSearchIndexBackgroundJob.php

apps/federation/lib/BackgroundJob/GetSharedSecret.php

apps/federation/lib/BackgroundJob/RequestSharedSecret.php

apps/files/lib/Command/Scan.php

apps/files/lib/Command/ScanAppData.php

apps/files_sharing/lib/SharedStorage.php

..._trashbin/lib/Migration/Version1010Date20200630192639.php

apps/settings/lib/AppInfo/Application.php

apps/settings/lib/Controller/CheckSetupController.php

apps/user_ldap/lib/Access.php

apps/user_ldap/lib/ILDAPWrapper.php

apps/user_ldap/lib/LDAP.php

build/integration/features/bootstrap/BasicStructure.php

build/integration/features/bootstrap/Trashbin.php