trying to reduce docs to matrix

.gitlab-ci.yml

@@ -28,6 +28,12 @@ stages:
       - CATALOG: ["1", "2", "3"]
 
 
+.parallel_docs: &parallel_docs
+  parallel:
+    matrix:
+      - TYPE: ["latest", "reference", "stable"]
+
+
 variables:
   PIP_CACHE_DIR: "${CI_PROJECT_DIR}/.cache/pip"
   XDG_CACHE_HOME: "${CI_PROJECT_DIR}/.cache"
@@ -351,6 +357,7 @@ coverage:
 # -- docs
 
 .docs:
+  <<: *parallel_docs
   # https://computing.docs.ligo.org/gitlab-ci-templates/python/#.python:sphinx
   extends: .python:sphinx
   image: python:3.9