fix(postgresql.conf): revert the location of include_dir back to absolute path

Author: hunleyd

ansible/files/postgresql_config/postgresql.conf.j2

@@ -158,4 +158,4 @@ jit_provider = 'llvmjit'		# JIT library to use
 # default postgresql.conf.  Note that these are directives, not variable
 # assignments, so they can usefully be given more than once.
 
-include_dir = '../postgresql-custom'			# include files ending in '.conf' from a directory, e.g., 'conf.d'
+include_dir = '/etc/postgresql-custom'			# include files ending in '.conf' from a directory, e.g., 'conf.d'