php70: 7.0.27 -> 7.0.28

Security patches: http://www.php.net/ChangeLog-7.php#7.0.28

pkgs/development/interpreters/php/default.nix

···
   };
 
   php70 = generic {
-    version = "7.0.27";
-    sha256 = "0ca174kp2l3fjcp8z0mqnkbjfhijjzz7rs7bkzg1qk2cpdijbylr";
+    version = "7.0.28";
+    sha256 = "0zrw0saqlfv60f3nmff7288wqfhdsfiqns4ys3ii0drzc6s92m5f";
   };
 
   php71 = generic {