sandbox: loosen restriction around Xcode caching

It doesn't really need to be as tight as it is currently, certainly outside brew
you can write to here without any special privileges beside being the user,
and being so can tight can cause issues on clean systems or systems where
Xcode hasn't been used before as exposed by https://github.com/Homebrew/homebrew-core/issues/4892.

Closes https://github.com/Homebrew/homebrew-core/issues/4892.

Library/Homebrew/sandbox.rb

@@ -77,7 +77,7 @@ class Sandbox
 
   # Xcode projects expect access to certain cache/archive dirs.
   def allow_write_xcode
-    allow_write_path "/Users/#{ENV["USER"]}/Library/Developer/Xcode/DerivedData/"
+    allow_write_path "/Users/#{ENV["USER"]}/Library/Developer"
   end
 
   def allow_write_log(formula)