chore(pipeline): update net5 version to preview 7 for codeql analysis (#205)

Author: ratanparai

.github/workflows/codeql-analysis.yml

@@ -21,7 +21,7 @@ jobs:
 
     - uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: '5.0.100-preview.6.20318.15'
+        dotnet-version: '5.0.100-preview.7.20366.6'
 
     # If this run was triggered by a pull request event, then checkout
     # the head of the pull request instead of the merge commit.