fix: add missing step to release docs (#1346)

book/src/developers/contributing/releases/deployment.md

@@ -9,6 +9,7 @@
  python3 -m venv venv
  . venv/bin/activate
  pip install ansible
+ pip install docker
  sudo apt install ansible-core
  ```
  On mac you can do `brew install ansible` instead of `apt`.