CI should check that the C documentation is up to date

[carsten-wenderdel]

When crates/wildbg-c/src/lib.rs is changed, then typically crates/wildbg-c/wildbg.h needs to be updated as well. The CI should check this and run cbindgen whenever unit tests and linting are checked.

The command used for that should probably be the one currently mentioned in lib.rs:
cbindgen --config cbindgen.toml --crate wildbg-c --output crates/wildbg-c/wildbg.h --lang c