Bump to rayon 0.8.

Author: bholley

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "jpeg-decoder"
-version = "0.1.12"
+version = "0.1.13"
 authors = ["Ulf Nilsson <kaksmet@gmail.com>"]
 description = "JPEG decoder"
 documentation = "https://docs.rs/jpeg-decoder"
@@ -12,7 +12,7 @@ exclude = ["tests/*"]
 
 [dependencies]
 byteorder = "1.0"
-rayon = { version = "0.7", optional = true }
+rayon = { version = "0.8", optional = true }
 
 [dev-dependencies]
 docopt = "0.7"