deps: Fix Jekyll 4.3 changes

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
         fetch-depth: 0
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.0
+        ruby-version: '3.0'
     - uses: actions/setup-node@v3
       with:
         node-version: 16

_plugins/set_posts.rb

@@ -3,3 +3,28 @@
   c['posts'].docs.concat c['news'].docs
   c['posts'].docs.concat c['planet'].docs
 end
+
+# Also monkey-patch `jekyll doctor` command
+module Jekyll
+  module Commands
+    class Doctor
+      class << self
+        def conflicting_urls(site)
+          conflicting_urls = false
+          destination_map(site).each do |dest, paths|
+            next unless paths.uniq.size > 1
+
+            conflicting_urls = true
+            Jekyll.logger.warn "Conflict:",
+                               "The following destination is shared by multiple files."
+            Jekyll.logger.warn "", "The written file may end up with unexpected contents."
+            Jekyll.logger.warn "", dest.to_s.cyan
+            paths.each { |path| Jekyll.logger.warn "", " - #{path}" }
+            Jekyll.logger.warn ""
+          end
+          conflicting_urls
+        end
+      end
+    end
+  end
+end

assets/css/main.scss

@@ -1,6 +1,3 @@
----
----
-
 @charset "utf-8";
 
 @import "skin"; // skin