Bump Desktop macOS requirement to 10.13 (#35465)

Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>

data/variables/desktop.yml

@@ -1,5 +1,5 @@
 # Supported platforms
 
-mac-osx-versions: macOS 10.12 or later
+mac-osx-versions: macOS 10.13 or later
 
 windows-versions: Windows 7 64-bit or later