Change rustc specific version descriptions

ChJR · ChJR · commit d5e2c841ab95 · 2019-10-13T23:15:23.000+09:00
diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
@@ -19,7 +19,7 @@ The contents of the Development Guide include:
 
 RustPython requires the following:
 
-- Rust latest stable version (at least 1.38.0)
+- Rust latest stable version (e.g 1.38.0 at Oct 1st 2019)
     - To check Rust version: `rustc --version` 
     - If you have `rustup` on your system, enter to update to the latest
       stable version: `rustup update stable`
diff --git a/README.md b/README.md
@@ -16,7 +16,7 @@ A Python-3 (CPython >= 3.5.0) Interpreter written in Rust :snake: :scream:
 
 #### Check out our [online demo](https://rustpython.github.io/demo/) running on WebAssembly.
 
-RustPython requires Rust latest stable version (at least 1.38.0). 
+RustPython requires Rust latest stable version (e.g 1.38.0 at Oct 1st 2019). 
 To check Rust version: `rustc --version` If you wish to update,
 `rustup update stable`.
 
