Merge pull request #343 from davidalber/fix-internal-link

Fix internal link

Author: alexcrichton

posts/2018-12-06-Rust-1.31-and-rust-2018.md

@@ -40,7 +40,7 @@ post, so here's a table of contents:
 * [New website](#new-website)
 * [Library stabilizations](#library-stabilizations)
 * [Cargo features](#cargo-features)
-* [Contributors](#contributors-to-1310)
+* [Contributors](#contributors-to-131.0)
 
 ### Rust 2018