Fix typo in workflow description

Author: kurpicz

.github/workflows/doxygen.yml

@@ -20,12 +20,7 @@ jobs:
       with:
           doxyfile-path: docs/Doxyfile
           working-directory: .
-          addintional-packages:
-            - perl
-            - build-base
-            - texlive-full
-            - biblatex
-            - ghostscript
+          additional-packages: perl build-base texlive-full biblatex ghostscript
 
     # Deploy the HTML documentation to GitHub Pages
     - name: GH Pages Deployment