disable nightly tests

Author: arun3688

.github/workflows/FMITest.yml

@@ -13,7 +13,7 @@ jobs:
       matrix:
         python-version: ['3.12']
         os: ['ubuntu-latest', 'windows-latest']
-        omc-version: ['stable', 'nightly']
+        omc-version: ['stable']
 
     steps:
       - uses: actions/checkout@v5