Fix new linter errors

lib/codeql.js

@@ -247,7 +247,7 @@ async function getCodeQLForCmd(cmd, checkVersion) {
                 try {
                     result = JSON.parse(output);
                 }
-                catch (err) {
+                catch {
                     throw Error(`Invalid JSON output from \`version --format=json\`: ${output}`);
                 }
                 util.cacheCodeQlVersion(result);