Relax libsqlite3-sys version requirements

[lnicola]

• [x] I agree to follow the project's code of conduct.

• [ ] I added an entry to CHANGES.md if knowledge of this change could be valuable to users.

Not sure if it's actually a good idea, but it will match https://github.com/georust/proj/blob/main/proj-sys/Cargo.toml.

[lnicola]

Probably blocked on a proj-sys release.

[ChristianBeilschmidt]

Is there a way to test the minimum versions in the CI? Max versions are checked by the current CI.

Nevertheless, this should be fine to merge.

[lnicola]

There's a cargo flag to pick the minimum versions, but I don't think we call anything from that crate, so we'll be testing GDAL rather than our crate.

I think we have to wait until proj-sys gets a new release, because cargo seems to complain otherwise.