Fix deploy stage of CI

.drone.yml

@@ -1,4 +1,5 @@
 kind: pipeline
+type: docker
 name: default
 
 platform:
@@ -17,8 +18,8 @@ steps:
     image: rust:1.53.0-slim-bullseye
     commands:
       - apt-get -qq update && apt-get -yqq install pkg-config libssl-dev build-essential libsqlite3-dev python3.9 python3.9-venv
-      - cargo install --path yama
-      - cargo install --path datman
+      - cargo install -q --path yama
+      - cargo install -q --path datman
       - python3.9 -m venv testsuite/.venv
       - ./testsuite/.venv/bin/pip install -e testsuite
       - cd testsuite && ./.venv/bin/green
@@ -32,7 +33,8 @@ steps:
       DEPLOY_SSH_KEY:
         from_secret: DEPLOY_SSH_KEY
     commands: # warning! Doesn't seem to like hashed known_hosts...
-      - cargo install mdbook
+      - cargo install -q mdbook
+      - apt-get -qq update && apt-get -yqq install rsync
       - cd docs
       - mdbook build
       - echo "$DEPLOY_SSH_KEY" > /tmp/rsync_key