Use :git source for Jekyll theme.

Author: fniephaus

docs/site/Gemfile

@@ -2,7 +2,7 @@ source ENV.fetch("RUBYGEMS_MIRROR", "https://rubygems.org")
 
 gem "jekyll", "~> 4.3.4"
 
-gem "graal-languages-jekyll-theme"
+gem "graal-languages-jekyll-theme", git: "https://github.com/graalvm/graal-languages-jekyll-theme.git", branch: "main"
 
 group :jekyll_plugins do
   gem "jekyll-relative-links"

docs/site/Gemfile.lock

@@ -1,3 +1,11 @@
+GIT
+  remote: https://github.com/graalvm/graal-languages-jekyll-theme.git
+  revision: 1e8d5b675768ea158684474ef7a32a6ed8ce9baf
+  branch: main
+  specs:
+    graal-languages-jekyll-theme (0.2.0)
+      jekyll (~> 4.3)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -41,8 +49,6 @@ GEM
     google-protobuf (4.34.1-x86_64-linux-gnu)
       bigdecimal
       rake (~> 13.3)
-    graal-languages-jekyll-theme (0.1.0)
-      jekyll (~> 4.3)
     hashery (2.1.2)
     html-proofer (5.2.1)
       addressable (~> 2.3)
@@ -159,7 +165,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
-  graal-languages-jekyll-theme
+  graal-languages-jekyll-theme!
   html-proofer
   http_parser.rb (~> 0.6.0)
   jekyll (~> 4.3.4)