docs: Work around readthedocs/readthedocs-docker-images#107

readthedocs Docker containers have too old a Node.js version, but we can
install a newer one with Conda.

Author: tavianator

.readthedocs.yml

@@ -6,6 +6,9 @@ version: 2
 sphinx:
   configuration: docs/conf.py
 
+conda:
+  environment: docs/environment.yml
+
 formats: all
 
 python:

docs/environment.yml

@@ -0,0 +1,15 @@
+name: bistring
+channels:
+  - defaults
+dependencies:
+  - _libgcc_mutex=0.1=main
+  - _openmp_mutex=4.5=1_gnu
+  - ca-certificates=2021.7.5=h06a4308_1
+  - icu=68.1=h2531618_0
+  - libgcc-ng=9.3.0=h5101ec6_17
+  - libgomp=9.3.0=h5101ec6_17
+  - libstdcxx-ng=9.3.0=hd4cf53a_17
+  - libuv=1.40.0=h7b6447c_0
+  - nodejs=14.8.0=hda19d22_0
+  - openssl=1.1.1k=h27cfd23_0
+  - zlib=1.2.11=h7b6447c_3