Missing dependencies in pyproject.toml

`pyproject.toml` is missing dependencies. These are present in `environment.yml`. See the following list:

```
cgen
dask
cftime
psutil
netCDF4
zarr
tqdm
pymbolic (not sure but I think this is actually a missing cgen dependency?)
```

As an example, adding them can be done like so:
```
[project]
(...)
dependencies = [
"cgen",
"dask >= 2.0",
]
