Simplify RTD config

Author: astrofrog

.readthedocs.yaml

@@ -2,18 +2,11 @@ version: 2
 
 build:
   os: "ubuntu-22.04"
-  tools:
-    python: "mambaforge-4.10"
-
-conda:
-  environment: docs/rtd_environment.yaml
 
 sphinx:
   builder: html
   configuration: docs/conf.py
 
-# Install regular dependencies.
-# Then, install special pinning for RTD.
 python:
   system_packages: false
   install: