Add linux platform to Gemfile

Author: jansroka

Gemfile.lock

@@ -29,6 +29,7 @@ GEM
       ffi (>= 1.15.0)
     eventmachine (1.2.7)
     ffi (1.17.2-arm64-darwin)
+    ffi (1.17.2-x86_64-linux-gnu)
     fiber-annotation (0.2.0)
     fiber-local (1.1.0)
       fiber-storage
@@ -37,6 +38,9 @@ GEM
     google-protobuf (4.33.2-arm64-darwin)
       bigdecimal
       rake (>= 13)
+    google-protobuf (4.33.2-x86_64-linux-gnu)
+      bigdecimal
+      rake (>= 13)
     hashery (2.1.2)
     html-proofer (5.1.1)
       addressable (~> 2.3)
@@ -95,6 +99,8 @@ GEM
     metrics (0.15.0)
     nokogiri (1.19.0-arm64-darwin)
       racc (~> 1.4)
+    nokogiri (1.19.0-x86_64-linux-gnu)
+      racc (~> 1.4)
     parallel (1.27.0)
     parser (3.3.10.0)
       ast (~> 2.4.1)
@@ -143,6 +149,8 @@ GEM
     safe_yaml (1.0.5)
     sass-embedded (1.97.1-arm64-darwin)
       google-protobuf (~> 4.31)
+    sass-embedded (1.97.1-x86_64-linux-gnu)
+      google-protobuf (~> 4.31)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
     traces (0.18.2)
@@ -157,6 +165,7 @@ GEM
 
 PLATFORMS
   arm64-darwin-24
+  x86_64-linux
 
 DEPENDENCIES
   html-proofer