fix workflow try #4

Gemfile

@@ -1,9 +1,10 @@
 source 'https://rubygems.org'
+
+gem 'jekyll'
+
+# Core plugins that directly affect site building
 group :jekyll_plugins do
-    gem 'classifier-reborn'
-    gem 'jekyll'
     gem 'jekyll-archives'
-    gem 'jekyll-diagrams'
     gem 'jekyll-email-protect'
     gem 'jekyll-feed'
     gem 'jekyll-get-json'
@@ -15,19 +16,21 @@ group :jekyll_plugins do
     gem 'jekyll-regex-replace'
     gem 'jekyll-scholar'
     gem 'jekyll-sitemap'
-    gem 'jekyll-target-blank'
     gem 'jekyll-tabs'
     gem 'jekyll-toc'
     gem 'jekyll-twitter-plugin'
-    gem 'jekyll-redirect-from'
     gem 'jemoji'
-    gem 'mini_racer'
-    gem 'unicode_utils'
-    gem 'webrick'
-    gem 'jekyll-loading-lazy'
+
+    gem 'classifier-reborn'  # used for content categorization during the build
 end
+
+# Gems for development or external data fetching (outside :jekyll_plugins)
 group :other_plugins do
     gem 'css_parser'
     gem 'feedjira'
     gem 'httparty'
-end
+    gem 'observer'       # used by jekyll-scholar
+    gem 'ostruct'        # used by jekyll-twitter-plugin
+    # gem 'unicode_utils' -- should be already installed by jekyll
+    # gem 'webrick' -- should be already installed by jekyll
+end

_config.yml

@@ -160,22 +160,25 @@ keep_files:
   - .nojekyll
   - .git
 
+# Plug-ins
 # Plug-ins
 plugins:
   - jekyll-archives
-  - jekyll-diagrams
   - jekyll-email-protect
   - jekyll-feed
+  - jekyll-get-json
   - jekyll-imagemagick
+  - jekyll-jupyter-notebook
+  - jekyll-link-attributes
   - jekyll-minifier
   - jekyll-paginate-v2
+  - jekyll-regex-replace
   - jekyll/scholar
   - jekyll-sitemap
-  - jekyll-target-blank
+  - jekyll-tabs
+  - jekyll-toc
   - jekyll-twitter-plugin
-  - jekyll-redirect-from
   - jemoji
-  - jekyll-loading-lazy
 
 # Sitemap settings
 defaults:
@@ -269,9 +272,9 @@ imagemagick:
 # Jekyll Diagrams
 # -----------------------------------------------------------------------------
 
-jekyll-diagrams:
-    # configuration, see https://github.com/zhustec/jekyll-diagrams.
-    # feel free to comment out this section if not using jekyll diagrams.
+# jekyll-diagrams:
+#     # configuration, see https://github.com/zhustec/jekyll-diagrams.
+#     # feel free to comment out this section if not using jekyll diagrams.
 
 
 # -----------------------------------------------------------------------------