logging: Allow clippy::type-complexity warning

As the rust toolchain version bump to its 1.66.0 release raised a
warning about the type complexity used for the closure, and that's
something we don't want to change, let's ignore such warning in this
very specific case.

See:
https://rust-lang.github.io/rust-clippy/master/index.html#type_complexity

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

src/libs/logging/src/lib.rs

@@ -499,6 +499,7 @@ mod tests {
         let error_closure = |logger: &Logger, msg: String| error!(logger, "{}", msg);
         let critical_closure = |logger: &Logger, msg: String| crit!(logger, "{}", msg);
 
+        #[allow(clippy::type_complexity)]
         struct TestData<'a> {
             slog_level: slog::Level,
             slog_level_tag: &'a str,