fix: make lazy_sync_runner() pub(crate)

lazy_sync_runner() is now also used by the sync_builder thus
it cannot be private anymore. But we don't have to expose it
as public API.

Signed-off-by: mbodmer <marc.bodmer@email.ch>

Author: mbodmer

testcontainers/src/runners/sync_runner.rs

@@ -49,7 +49,7 @@ where
     }
 }
 
-pub fn lazy_sync_runner() -> Result<Arc<tokio::runtime::Runtime>> {
+pub(crate) fn lazy_sync_runner() -> Result<Arc<tokio::runtime::Runtime>> {
     let mut guard = ASYNC_RUNTIME
         .get_or_init(|| Mutex::new(Weak::new()))
         .lock()