Make `babel` a dependency for testbase #15

Job	Run time
test-windows (3.9, numpy>=1.21,<2.0.0)	1m 29s
test-macos (3.9)	5m 11s
test-windows (3.10, numpy>=1.21,<2.0.0)	1m 19s
test-linux (3.9)	4m 28s
test-macos (3.9, numpy>=1.21,<2.0.0)	5m 19s
test-windows (3.11, numpy>=1.21,<2.0.0)	1m 25s
test-linux (3.9, uncertainties==3.1.6)	3m 54s
test-macos (3.10)	5m 41s
test-linux (3.9, uncertainties>=3.1.6,<4.0.0)	3m 28s
test-macos (3.10, numpy>=1.21,<2.0.0)	6m 25s
test-macos (3.11)	5m 35s
test-linux (3.9, numpy>=1.21,<2.0.0)	3m 37s
test-macos (3.11, numpy>=1.21,<2.0.0)	5m 55s
test-linux (3.9, numpy>=1.21,<2.0.0, uncertainties==3.1.6)	4m 42s
test-linux (3.9, numpy>=1.21,<2.0.0, uncertainties>=3.1.6,<4.0.0)	5m 16s
test-linux (3.10)	5m 3s
test-linux (3.10, uncertainties==3.1.6)	4m 26s
test-linux (3.10, uncertainties>=3.1.6,<4.0.0)	4m 22s
test-linux (3.10, numpy>=1.21,<2.0.0)	5m 44s
test-linux (3.10, numpy>=1.21,<2.0.0, uncertainties==3.1.6)	5m 40s
test-linux (3.10, numpy>=1.21,<2.0.0, uncertainties>=3.1.6,<4.0.0)	5m 16s
test-linux (3.11)	4m 24s
test-linux (3.11, uncertainties==3.1.6)	5m 20s
test-linux (3.11, uncertainties>=3.1.6,<4.0.0)	6m 23s
test-linux (3.11, numpy>=1.21,<2.0.0)	4m 36s
test-linux (3.11, numpy>=1.21,<2.0.0, uncertainties==3.1.6)	7m 48s
test-linux (3.11, numpy>=1.21,<2.0.0, uncertainties>=3.1.6,<4.0.0)	6m 25s
test-linux (3.9, numpy, matplotlib==2.2.5)	4m 54s
test-linux (3.9, numpy, uncertainties, sparse xarray netCDF4 dask[complete]==2023.4.0 graphviz ba...	5m 22s
	2h 19m 27s

Provide feedback