Add FluxTraining 0.3 compat (#223)

Author: lorenzoh

Project.toml

@@ -56,7 +56,7 @@ FileIO = "1.7"
 FilePathsBase = "0.9"
 FixedPointNumbers = "0.8"
 Flux = "0.12, 0.13"
-FluxTraining = "0.2"
+FluxTraining = "0.2, 0.3"
 Glob = "1"
 ImageInTerminal = "0.4"
 ImageIO = "0.6"