docs: fix environment

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

docs/environment.yml

diff --git a/docs/environment.yml b/docs/environment.yml
index e79e4fb..715caaa 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -1,4 +1,4 @@
-# Copyright (C) 2021  The Symbiflow Authors.
+# Copyright (C) 2021  The SymbiFlow Authors.
 #
 # Use of this source code is governed by a ISC-style
 # license that can be found in the LICENSE file or at
@@ -8,21 +8,23 @@
 
 name: v2x-docs
 channels:
-- symbiflow
-- conda-forge
+  - defaults
+  - litex-hub
+  - conda-forge
 dependencies:
-- python=3.7
-- pip
-- pycairo
-- pango
-- pygobject
-- symbiflow-yosys
-- netlistsvg
-# ReadTheDocs dependencies (installed here but also by the docs build CI)
-- mock
-- pillow
-- sphinx
-- sphinx_rtd_theme
-# Packages installed from PyPI
-- pip:
-  - -r requirements.txt
+  - litex-hub::symbiflow-yosys
+  - python=3.7
+  - pip
+  - pycairo
+  - pango
+  - pygobject
+  - netlistsvg
+  - nodejs
+  # ReadTheDocs dependencies (installed here but also by the docs build CI)
+  - mock
+  - pillow
+  - Sphinx=3.3.0
+  - sphinx_rtd_theme
+  # Packages installed from PyPI
+  - pip:
+    - -r requirements.txt