gitpod.io fixes (#3456)

- Ignore user prompt for install
- Install pyyaml
- Fix demo data installation

.gitpod.yml

@@ -7,12 +7,13 @@ tasks:
       export INVENTREE_STATIC_ROOT='/workspace/InvenTree/dev/static'
       export PIP_USER='no'
 
-      sudo apt install gettext
+      sudo apt install -y gettext
       python3 -m venv venv
       source venv/bin/activate
-      pip install invoke
+      pip install invoke pyyaml
       mkdir dev
-      inv setup-test
+      invoke update
+      invoke setup-test --ignore-update --path inventree-data
       gp sync-done start_server
 
  - name: Start server