Revert "pin pymatgen to 2023.7.11" (#504)

Reverts #501

Let's see if the error got fixed.

Author: njzjz

.github/workflows/test.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Install rdkit
       run: python -m pip install rdkit openbabel-wheel
     - name: Install dependencies
-      run: python -m pip install .[amber,ase,pymatgen] coverage "pymatgen==2023.7.11;python_version>='3.8'"
+      run: python -m pip install .[amber,ase,pymatgen] coverage
     - name: Test
       run: cd tests && coverage run --source=../dpdata -m unittest && cd .. && coverage combine tests/.coverage && coverage report
     - name: Run codecov