Revert "Remove {{ project_name }} from package.json since django project-template does not replace it"
Revert "Remove {{ project_name }} from package.json since django project-template does not replace it"

This reverts commit 0f6eb1ebaaa11a73befb1173972f9d1a79ba8374.

leukeleu/wagtail-startproject,leukeleu/wagtail-startproject