Remove no-longer using variable: project_ids

Author: yasulab

tasks/upsert_project_pages_by_data.rb

@@ -11,7 +11,6 @@
 #Dir.glob("_posts/exhibition/*.md").each { |filename| File.delete(filename) }
 
 projects = YAML.load_file('_data/projects.yml', symbolize_names: true)
-project_ids = (1..(projects.count)).to_a # ナビ用の配列（ID=1, ID=2, ..., ID=n）を作る
 projects.each.with_index(0) do |project, index|
   # Generate individual project page by data
   project_prev = projects.rotate(index - 1).first