flag lammps.has_package() python method as new

doc/src/pair_pace.rst

@@ -112,7 +112,6 @@ requests to compute `gamma`, as shown in example below:
     compute max_pace_gamma all reduce max f_pace_gamma
     variable dump_skip equal "c_max_pace_gamma < 5"
 
-
     dump pace_dump all custom 20 extrapolative_structures.dump id x y z f_pace_gamma
     dump_modify pace_dump skip v_dump_skip
 

python/lammps/core.py

@@ -1634,6 +1634,8 @@ class lammps(object):
     This is a wrapper around the :cpp:func:`lammps_config_has_package`
     function of the library interface.
 
+    .. versionadded:: TBD
+
     :param name: name of the package
     :type  name: string