Add composer alias for D8 compatibility

Getting

Your requirements could not be resolved to an installable set of packages.

Problem 1
    - Can only install one of: easyrdf/easyrdf[1.0.0-rc.1, 0.9.1].
    - Can only install one of: easyrdf/easyrdf[1.0.0-rc.1, 0.9.1].
    - Can only install one of: easyrdf/easyrdf[1.0.0-rc.1, 0.9.1].
    - drupal/rdfui 1.x-dev requires easyrdf/easyrdf 1.0.0-rc.1 as 0.9.1 -> satisfiable by easyrdf/easyrdf[1.0.0-rc.1].
    - Installation request for drupal/rdfui 1.x-dev -> satisfiable by drupal/rdfui[1.x-dev].
    - Installation request for easyrdf/easyrdf (locked at 0.9.1) -> satisfiable by easyrdf/easyrdf[0.9.1].

Fixed it by adding to composer.json

"easyrdf/easyrdf": "1.0.0-rc.1 as 0.9.1",

I think this alias can be removed now that EasyRDF has released v1.0.0 https://github.com/easyrdf/easyrdf/releases/tag/1.0.0

This alias now breaks my project, see proposed patch https://www.drupal.org/project/rdfui/issues/3172502

When updating the composer lock file, or requiring a new module, thes module throws an error :

[RuntimeException]                                                                                                                                                                                               
  Could not load package drupal/rdfui in https://packages.drupal.org/8: [UnexpectedValueException] Could not parse version constraint ^1.0 as 0.9.1: Invalid version string "^1.0" in "^1.0 as 0.9.1", the alias   
  source must be an exact version, if it is a branch name you should prefix it with dev-

The alias has been removed in #3172502: Couldn't install 'rdfui' in Drupal 8.9.3. .