Fix pretty docs

Author: kasperpeulen

.circleci/config.yml

@@ -539,6 +539,10 @@ jobs:
                 keys:
                     - prettydocs-yarn-2-cache-v8--{{ checksum "yarn.lock" }}
                 name: Restore Yarn cache
+            - run:
+                  command: |
+                      yarn install
+                  name: Install
             - save_cache:
                 key: prettydocs-yarn-2-cache-v8--{{ checksum "yarn.lock" }}
                 name: Save Yarn cache