Incompatible with GCC 9.3.0

When setting the compiler in the make file from gcc@8.3.0 to gcc@9.3.0, the tests fail. This is the log:
============================= test session starts ==============================
platform linux -- Python 3.9.7, pytest-7.1.2, pluggy-1.0.0
rootdir: /scratch/snx3000/jenkins/workspace/iconvis_testsuite, configfile: setup.cfg
collected 5 items

icon_vis/icon_vis/modules/tests/test_grib.py FF                          [ 40%]
icon_vis/icon_vis/modules/tests/test_netcdf.py ...                       [100%]

=================================== FAILURES ===================================
________________________________ test_grid_edge ________________________________

    def test_grid_edge():

        _ds_cell, ds_edge = open_file(f_alldata)

        ds_edgevars = iconvis.combine_grid_information(ds_edge, f_grid)

>       assert list(ds_edgevars.data_vars) == [
            "VN",
            "VT",
        ], "ds_edgevars should only have two data variables, ['VN', 'VT']"
E       AssertionError: ds_edgevars should only have two data variables, ['VN', 'VT']
E       assert ['unknown'] == ['VN', 'VT']
E         At index 0 diff: 'unknown' != 'VN'
E         Right contains one more item: 'VT'
E         Full diff:
E         - ['VN', 'VT']
E         + ['unknown']

icon_vis/icon_vis/modules/tests/test_grib.py:32: AssertionError
________________________________ test_grid_cell ________________________________

    def test_grid_cell():

        ds_cell, _ds_edge = open_file(f_alldata)

        ds_cellvars = iconvis.combine_grid_information(ds_cell, f_grid)

>       assert list(ds_cellvars.data_vars) == [
            "P",
            "T",
            "U",
            "V",
            "QV",
            "QC",
            "QI",
        ], "ds_cellvars should only have two data variables, ['P', 'T', 'U', 'V', 'QV', 'QC', 'QI']"
E       AssertionError: ds_cellvars should only have two data variables, ['P', 'T', 'U', 'V', 'QV', 'QC', 'QI']
E       assert ['unknown', '...'v', 'q', ...] == ['P', 'T', 'U...V', 'QC', ...]
E         At index 0 diff: 'unknown' != 'P'
E         Full diff:
E         - ['P', 'T', 'U', 'V', 'QV', 'QC', 'QI']
E         + ['unknown', 'pres', 't', 'u', 'v', 'q', 'clwmr']

icon_vis/icon_vis/modules/tests/test_grib.py:60: AssertionError
=========================== short test summary info ============================
FAILED icon_vis/icon_vis/modules/tests/test_grib.py::test_grid_edge - Asserti...
FAILED icon_vis/icon_vis/modules/tests/test_grib.py::test_grid_cell - Asserti...
==================== 2 failed, 3 passed in 95.50s (0:01:35) ====================
C2SM / icon-vis

Incompatible with GCC 9.3.0 #20
