Add doc script downloading

gitlab/install.sh

@@ -52,7 +52,7 @@ get_exec() {
 run_cmd mkdir -pv ${1}
 get_script ${1} functions.sh
 get_exec ${1} install.sh
-for stage in "build" "test" "wheels" "deploy"; do
+for stage in "build" "test" "docs" "wheels" "deploy"; do
   get_exec ${1} before_${stage}.sh
   get_exec ${1} ${stage}.sh
   get_exec ${1} after_${stage}.sh