add ffmpeg to dependencies

basnijholt · basnijholt · commit a4d51faa474f · 2021-09-23T19:44:08.000+02:00
diff --git a/docs/environment.yml b/docs/environment.yml
@@ -20,3 +20,4 @@ dependencies:
   - sphinx=4.2.0
   - m2r2=0.3.1
   - sphinx_rtd_theme=1.0.0
+  - ffmpeg=4.3.2
