fix rtd build

.github/workflows/docs.yaml

@@ -34,7 +34,7 @@ jobs:
 
     - name: install package deps
       run: |
-        mamba install numpy scipy pytest pytest-cov codecov six sphinx
+        mamba install numpy scipy pytest pytest-cov codecov sphinx
         pip install sphinx-sitemap sphinx-rtd-theme
 
     - name: check install

.readthedocs.yml

@@ -0,0 +1,20 @@
+# .readthedocs.yml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Build documentation in with Sphinx
+sphinx:
+  configuration: doc/source/conf.py
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "mambaforge-4.10"
+
+# Optionally set the version of Python and requirements required to build your docs
+conda:
+  environment: ci/environment.yml

ci/environment.yaml

@@ -0,0 +1,12 @@
+name: griddata_env
+channels:
+  - conda-forge
+dependencies:
+  - pip
+  - numpy>=1.21
+  - scipy
+  - mcrfile
+  - sphinx<7.0
+  - pip:
+    - sphinx-sitemap
+    - sphinx-rtd-theme