feat: reexport prost

Signed-off-by: yjhmelody <[email protected]>

src/encoding/protobuf.rs

@@ -22,6 +22,10 @@
 //! assert_eq!("This is my counter.", family.help);
 //! ```
 
+
+// re-export
+pub use prost;
+
 // Allowing some lints here as the `openmetrics.rs` is an automatically generated file.
 #[allow(missing_docs, clippy::derive_partial_eq_without_eq)]
 /// Data models that are automatically generated from OpenMetrics protobuf