update Gemfile to jekyll 4

docs/Gemfile

@@ -1,4 +1,4 @@
 source 'https://rubygems.org'
 
-gem "jekyll", ">= 3.6.3"
+gem "jekyll", ">= 4.0.0"
 

docs/Gemfile.lock

@@ -13,10 +13,6 @@ GEM
     forwardable-extended (2.6.0)
     google-protobuf (3.25.2)
     google-protobuf (3.25.2-aarch64-linux)
-    google-protobuf (3.25.2-arm64-darwin)
-    google-protobuf (3.25.2-x86-linux)
-    google-protobuf (3.25.2-x86_64-darwin)
-    google-protobuf (3.25.2-x86_64-linux)
     http_parser.rb (0.8.0)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
@@ -52,65 +48,29 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (5.0.4)
+    rake (13.1.0)
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     rexml (3.2.6)
     rouge (4.2.0)
     safe_yaml (1.0.5)
-    sass-embedded (1.70.0-aarch64-linux-android)
+    sass-embedded (1.70.0)
       google-protobuf (~> 3.25)
+      rake (>= 13.0.0)
     sass-embedded (1.70.0-aarch64-linux-gnu)
       google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-aarch64-linux-musl)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-arm-linux-androideabi)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-arm-linux-gnueabihf)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-arm-linux-musleabihf)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-arm64-darwin)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86-linux-android)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86-linux-gnu)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86-linux-musl)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86_64-darwin)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86_64-linux-android)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86_64-linux-gnu)
-      google-protobuf (~> 3.25)
-    sass-embedded (1.70.0-x86_64-linux-musl)
-      google-protobuf (~> 3.25)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
     unicode-display_width (2.5.0)
     webrick (1.8.1)
 
 PLATFORMS
-  aarch64-linux-android
-  aarch64-linux-gnu
-  aarch64-linux-musl
-  arm-linux-androideabi
-  arm-linux-gnueabihf
-  arm-linux-musleabihf
-  arm64-darwin
-  x86-linux
-  x86-linux-android
-  x86-linux-gnu
-  x86-linux-musl
-  x86_64-darwin
-  x86_64-linux
-  x86_64-linux-android
-  x86_64-linux-gnu
-  x86_64-linux-musl
+  aarch64-linux
+  ruby
 
 DEPENDENCIES
-  jekyll (>= 3.6.3)
+  jekyll (>= 4.0.0)
 
 BUNDLED WITH
    2.5.4