Upgrade to Ehcache3 3.11.1.

Comment From: snicoll

I've discovered an odd behavior that I've reported to the EhCache team: https://github.com/ehcache/ehcache3/issues/3272

In the meantime, we'll pause the upgrade.

Comment From: HyunSangHan

Would it be okay if I give this a try? I checked the Ehcache issue, and it looks like the problem has been already fixed in version 3.11.1.

Comment From: snicoll

Thanks but we don't need contributions for dependency upgrades.