Add Slack notification

.drone.yml

@@ -6,6 +6,9 @@ pipeline:
     dockerfile: .dockerfile
     tags:
       - latest
+  slack:
+    image: plugins/slack
+    secrets: [ slack_webhook ]
   # tests to ensure they compile independently
   test-neovim:
     group: test

.install/zsh-pure.sh

@@ -7,7 +7,7 @@ echo
 echo "Installing pure-prompt for ZSH..."
 echo
 
-mkdir /usr/local/share/zsh/site-functions/
+mkdir -p /usr/local/share/zsh/site-functions
 curl -fLo /usr/local/share/zsh/site-functions/prompt_pure_setup \
 	https://raw.githubusercontent.com/sindresorhus/pure/master/pure.zsh
 curl -fLo /usr/local/share/zsh/site-functions/async \