bundle install explicitly added to workflow config

Author: ehsk

.github/workflows/deploy.yml

@@ -89,6 +89,7 @@ jobs:
           sudo apt-get update && sudo apt-get install -y imagemagick
           pip3 install --upgrade nbconvert
           export JEKYLL_ENV=production
+          bundle install
           bundle exec jekyll build
       - name: Purge unused CSS 🧹
         run: |