🐛 fix: remove unsupported generatedAt from coverage badge json

Author: aelf-hzz780

bin/generate-coverage-badge.ts

@@ -36,7 +36,6 @@ const badge = {
   label: 'coverage',
   message: `${rounded}%`,
   color,
-  generatedAt: new Date().toISOString(),
 };
 
 fs.mkdirSync(outputDir, { recursive: true });