README: Update copyright

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>

Author: rye

README.md

@@ -47,7 +47,7 @@ We will release version 1.0 when the GitHub milestone has been fully resolved.
 
 ## License
 
-> Copyright © 2019 Kristofer J. Rye
+> Copyright © 2019—2022 Kristofer J. Rye
 
 This software is released under either of: