fix: Only use net9.0 for ci/cd

Author: linkdotnet

.github/workflows/codeql.yml

@@ -29,8 +29,6 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: |
-            7.0.x
-            8.0.x
             9.0.x
 
       - name: Initialize CodeQL

.github/workflows/dotnet.yml

@@ -25,8 +25,6 @@ jobs:
       uses: actions/setup-dotnet@v4
       with:
         dotnet-version: |
-          7.0.x
-          8.0.x
           9.0.x
     - name: Restore dependencies
       run: dotnet restore