Update kernel version reported by uname -r

### Description

Currently gVisor reports the kernel version as `4.4.0` and this version hasn't been updated in 5+ years: https://github.com/google/gvisor/commit/ebe8001724a6965cc9723604b38f42563d284a6a

I'm wondering about a couple things:

1. Could this version number be bumped higher?
2. Is it possible to comment on this value why the version is set at this version and what the policy is around updating it?

### Is this feature related to a specific bug?

No specific bug, but a user thought we were running a very old (2016) Linux kernel and that prompted me to look into this 🙂.

### Do you have a specific solution in mind?

_No response_