Added Test for Zn.

nomad/normalizing/repository.py

tests/data/parsers/vasp/GeZnNa2_Test/CHG.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/CHGCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/CONTCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/DOSCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/EIGENVAL.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/INCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/KPOINTS.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/OUTCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/POSCAR.relax1.bz2

tests/data/parsers/vasp/GeZnNa2_Test/vasprun.xml.relax1

tests/test_parsing.py