Accept expected diagnostic output

Author: mbg

csharp/ql/integration-tests/linux/diag_nuget_config_casing/diagnostics.expected

@@ -26,3 +26,17 @@
     "telemetry": true
   }
 }
+{
+  "markdownMessage": "On platforms with case-sensitive file systems, NuGet only accepts files with one of the following names: nuget.config, NuGet.config, NuGet.Config.\n\nCodeQL found the following files while performing an analysis on a platform with a case-sensitive file system:\n\n- `<test-root-directory>/sub-project/Nuget.Config`\n\nTo avoid unexpected results, rename these files to match the casing of one of the accepted filenames.",
+  "severity": "warning",
+  "source": {
+    "extractorName": "csharp",
+    "id": "csharp/autobuilder/buildless/case-sensitive-nuget-config",
+    "name": "Found NuGet configuration files which are not correctly named"
+  },
+  "visibility": {
+    "cliSummaryTable": true,
+    "statusPage": true,
+    "telemetry": true
+  }
+}