Mark result of appendExtraQueryExclusions as Readonly to prevent further modification

Author: mbg

src/config-utils.ts

@@ -1489,7 +1489,7 @@ export function generateCodeScanningConfig(
 export function appendExtraQueryExclusions(
   extraQueryExclusions: ExcludeQueryFilter[],
   cliConfig: UserConfig,
-): UserConfig {
+): Readonly<UserConfig> {
   if (extraQueryExclusions.length === 0) {
     return cliConfig;
   }