兼容Android15 v3

Release v2.0.8: Fix FileDownloader NoClassDefFoundError

This release fixes the critical NoClassDefFoundError issue with FileDownloader classes:

New Features:
- Enhanced dependency resolution for FileDownloader library
- Improved ProGuard configuration to prevent class obfuscation
- Better publishing configuration for JitPack compatibility

Bug Fixes:
- Fixed FileDownloadUrlConnection class not found error
- Resolved runtime crashes in AppUpdateUtils.init() method
- Fixed dependency inclusion in final APK

Breaking Changes:
- None - fully backward compatible

Migration Guide:
- Update your dependency to v2.0.8
- Ensure you have the latest ProGuard rules if using obfuscation