Build: Bump version to 4.0.8.0 in Package.appxmanifest

Author: yaira2

src/Files.App (Package)/Package.appxmanifest

@@ -16,7 +16,7 @@
     <Identity
         Name="FilesDev"
         Publisher="CN=Files"
-        Version="4.0.7.0" />
+        Version="4.0.8.0" />
 
     <Properties>
         <DisplayName>Files - Dev</DisplayName>