Change rand version to '*'

bengesoff · bengesoff · commit 7150d3cd9e01 · 2015-05-07T14:23:05.000+01:00
Following paragraph says "we've used `*` which..." but code says "rand=\"0.3.0\""
diff --git a/src/doc/trpl/guessing-game.md b/src/doc/trpl/guessing-game.md
@@ -352,7 +352,7 @@ add these few lines at the bottom:
 ```toml
 [dependencies]
 
-rand="0.3.0"
+rand="*"
 ```
 
 The `[dependencies]` section of `Cargo.toml` is like the `[package]` section:
