Safer deploy version names

Huh, I was previously using ISO timestamps, but it turns out Yarn doesn't handle binary paths very reliably when your folder names contain colons 😳 so `canvas` was failing with `node-gyp not found`

I've documented it here in this self-answered StackOverflow question, so hopefully the next future person searching will find my answer! https://stackoverflow.com/q/69819597/107415

deploy/playbooks/deploy.yml

@@ -17,7 +17,7 @@
       when: not skip_build
 
     - name: Generate a version name from the current timestamp
-      command: date '+%Y-%m-%dT%H:%M:%S'
+      command: date '+%Y-%m-%d-%s'
       register: new_app_version
 
     - name: Print out the new version name