env minor typo

Let's leave pandas version unconstrained in the recommended environment. I think we should frankly do the same for Python, changing these two lines to:
```yml
name: hsp2
  - python >=3.10
```

environment.yml

@@ -17,7 +17,7 @@ dependencies:
   - python =3.10
   - scipy  # Scipy also installs numpy
   # Pandas installs most scientific Python modules, such as Numpy, etc.
-  - pandas 2
+  - pandas
   - numba
   - numpy
   - hdf5