Change: Update dependencies and require Go 1.23 or newer

We have updated all dependencies. Since some libraries require newer Go
standard library features, support for Go 1.19, 1.20, 1.21 and 1.22 has been
dropped, which means that restic now requires at least Go 1.23 to build.

This also disables support for TLS versions older than TLS 1.2. On Windows,
restic now requires at least Windows 10 or Windows Server 2016. On macOS,
restic now requires at least macOS 11 Big Sur.

https://github.com/restic/restic/pull/4938