diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 27b78e70..0936b8de 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -41,7 +41,7 @@ jobs:
         if: ${{ runner.os != 'Windows' }}
         uses: actions/setup-python@v2
         with:
-          python-version: '2.x'
+          python-version: '3.x'
 
       - name: Install docutils for Github-Markup
         if: ${{ runner.os != 'Windows' }}
diff --git a/Gemfile b/Gemfile
index dbc3cac9..73addbc0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,4 +9,4 @@ gem "org-ruby", "~> 0.9.12"
 gem "creole", "~> 0.5.0"
 gem "wikicloth", "~> 0.8.3"
 gem "asciidoctor", "~> 2.0"
-gem "github-markup", "~> 3.0"
+gem "github-markup", "~> 4.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index f6e8d11f..049eba42 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -24,7 +24,7 @@ GEM
       escape_utils (~> 1.2.0)
       mini_mime (~> 1.0)
       rugged (>= 0.25.1)
-    github-markup (3.0.5)
+    github-markup (4.0.0)
     htmlentities (4.3.4)
     i18n (1.8.9)
       concurrent-ruby (~> 1.0)
@@ -84,7 +84,7 @@ DEPENDENCIES
   commonmarker (~> 0.21.0)
   creole (~> 0.5.0)
   github-linguist (>= 7.12.1)
-  github-markup (~> 3.0)
+  github-markup (~> 4.0)
   licensee (>= 9.9.0)
   org-ruby (~> 0.9.12)
   rdoc (= 3.12.1)