fix(config): update file mode in group shared cache (#4796)

content/docs/user-guide/project-structure/configuration.md

@@ -201,7 +201,7 @@ section):
 
 - `cache.shared` - permissions for newly created or downloaded cache files and
   directories. The only accepted value right now is `group`, which makes DVC use
-  `664` (rw-rw-r--) for files and `775` (rwxrwxr-x) for directories. This is
+  `444` (r--r--r--) for files and `775` (rwxrwxr-x) for directories. This is
   useful when [sharing a cache] among projects. The default permissions for
   cache files is system dependent. In Linux and macOS for example, they're
   determined using [`os.umask`].