Update deploy-docs.yml

Author: seongee702

.github/workflows/deploy-docs.yml

@@ -43,7 +43,7 @@ jobs:
       - name: Install gettext tools
         run: |
           sudo apt-get update
-          sudo apt-get install -y gettext
+          sudo apt-get install -y gettext graphviz
 
       - name: Build translated documentation
         run: |