remove support for nightlies

Author: damienwebdev

.github/workflows/ci.yml

@@ -23,10 +23,6 @@ jobs:
           - magento_version: ">=2.4.8 <2.4.9"
             repository_url: "https://mirror.mage-os.org/"
             stability: ""
-          - magento_version: ""
-            repository_url: "https://upstream-nightly.mage-os.org/"
-            stability: "alpha"
-            name: "nightly"
 
     name: Existing Project ${{ matrix.name || matrix.magento_version }}