This PR updates the version of go used in builds and docker to
1.23.0. Release notes: https://go.dev/doc/go1.23
More importantly, following our policy of maintaining the last two
versions (which now becomes 1.23 and 1.22), we can now make use of
the things that were introduced in 1.22: https://go.dev/doc/go1.22
Go 1.22 makes two changes to “for” loops.
- each iteration creates new variables,
- for loops may range over integers
Other than that, some interesting library changes and other stuff.
