feat(core): Default encoding/decoding limits (#1335)

* feat(core): Default encoding/decoding limits

This PR adds new defaults for both client and server max
encoding/decoding message size limits. By default, the max message
decoding size is `4MB` and the max message encoding size is
`usize::MAX`.

This is follow up work from https://github.com/hyperium/tonic/pull/1274

BREAKING: Default max message encoding/decoding limits

* update generated code

tonic-reflection/src/generated/grpc.reflection.v1alpha.rs

@@ -212,12 +212,16 @@ pub mod server_reflection_client {
             self
         }
         /// Limits the maximum size of a decoded message.
+        ///
+        /// Default: `4MB`
         #[must_use]
         pub fn max_decoding_message_size(mut self, limit: usize) -> Self {
             self.inner = self.inner.max_decoding_message_size(limit);
             self
         }
         /// Limits the maximum size of an encoded message.
+        ///
+        /// Default: `usize::MAX`
         #[must_use]
         pub fn max_encoding_message_size(mut self, limit: usize) -> Self {
             self.inner = self.inner.max_encoding_message_size(limit);
@@ -330,12 +334,16 @@ pub mod server_reflection_server {
             self
         }
         /// Limits the maximum size of a decoded message.
+        ///
+        /// Default: `4MB`
         #[must_use]
         pub fn max_decoding_message_size(mut self, limit: usize) -> Self {
             self.max_decoding_message_size = Some(limit);
             self
         }
         /// Limits the maximum size of an encoded message.
+        ///
+        /// Default: `usize::MAX`
         #[must_use]
         pub fn max_encoding_message_size(mut self, limit: usize) -> Self {
             self.max_encoding_message_size = Some(limit);