Remove conda-forge from environment channels.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>

docs/environment.yml

diff --git a/docs/environment.yml b/docs/environment.yml
index cef4cf1..c8db8b8 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -16,7 +16,6 @@
 name: skywater-pdk-docs
 channels:
 - symbiflow
-- conda-forge
 - defaults
 dependencies:
 - python=3.8