Update readme for ttrpc-codegen and compiler

Add version table.

Signed-off-by: Tim Zhang <tim@hyper.sh>

Author: Tim-Zhang

compiler/README.md

@@ -6,3 +6,9 @@ generate rust version ttrpc code from proto files.
 
 - [Manual Generation](https://github.com/containerd/ttrpc-rust#1-generate-with-protoc-command) uses ttrpc-compiler as a protoc plugin
 - [Programmatic Generation](https://github.com/containerd/ttrpc-rust#2-generate-programmatically) uses ttrpc-compiler as a rust crate
+
+## Versions
+| ttrpc-compiler version | ttrpc version |
+| ------------- | ------------- |
+| 0.3.x | <= 0.4.x  |
+| 0.4.x  | >= 0.5.x

ttrpc-codegen/README.md

@@ -2,13 +2,20 @@
 
 API to generate `.rs` files to be used e. g. [from build.rs](../example/build.rs).
 
-Example code:
+## Example
+
+build.rs:
 
 ```rust
 use ttrpc_codegen::Codegen;
-use ttrpc_codegen::Customize;
+use ttrpc_codegen::{Customize, ProtobufCustomize};
 
 fn main() {
+    let protos = vec![
+        "protos/a.proto",
+        "protos/b.proto",
+    ];
+
     Codegen::new()
         .out_dir("protocols/sync")
         .inputs(&protos)
@@ -17,19 +24,29 @@ fn main() {
         .customize(Customize {
             ..Default::default()
         })
+        .rust_protobuf_customize(ProtobufCustomize {
+            ..Default::default()
+        }
         .run()
         .expect("Gen code failed.");
 }
 
 ```
 
-And in `Cargo.toml`:
+Cargo.toml:
 
 ```
 [build-dependencies]
-ttrpc-codegen = "0.3"
+ttrpc-codegen = "0.2"
 ```
 
+## Versions
+| ttrpc-codegen version | ttrpc version |
+| ------------- | ------------- |
+| 0.1.x | <= 0.4.x  |
+| 0.2.x  | >= 0.5.x  |
+
+## Alternative
 The alternative is to use
 [protoc-rust crate](https://github.com/stepancheg/rust-protobuf/tree/master/protoc-rust),
 which relies on `protoc` command to parse descriptors. Both crates should produce the same result,