Update start date

Co-Authored-By: Manish Goregaokar <[email protected]>

Author: Mark-Simulacrum

text/0000-roadmap-2020.md

@@ -1,7 +1,7 @@
 # Rust 2020 Roadmap RFC Draft
 
 - Feature Name: N/A
-- Start Date: 2019-01-22
+- Start Date: 2020-01-22
 - RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
 - Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
 
@@ -393,4 +393,3 @@ be figured out as the work proceeds, which doesn't really apply here.
 [future-possibilities]: #future-possibilities
 
 Not applicable.
-