[BACKPORT] [DOC] Update instructions for installation via conda (#125) (#126)

Author: tsbinns

docs/source/installation.rst

@@ -8,6 +8,13 @@ then install it using `pip <https://pip.pypa.io/en/stable/>`_:
     
     pip install pybispectra
 
+or `conda <https://docs.conda.io/en/latest/>`_ from
+`conda-forge <https://anaconda.org/conda-forge>`_ (for PyBispectra >= 1.2.2):
+
+.. code-block::
+    
+    conda install -c conda-forge pybispectra
+
 PyBispectra requires Python >= 3.10.
 
 If you need to create an environment in which to install PyBispectra, you can do so
@@ -24,8 +31,7 @@ In a shell with ``conda`` available, run the following commands:
 
     conda create -n pybispectra_env
     conda activate pybispectra_env
-    conda install -c conda-forge pip
-    pip install pybispectra
+    conda install -c conda-forge pybispectra
 
 With ``venv``
 -------------