Install fonts needed for LaTeX step

Author: DanielKotik

.github/workflows/gh-pages.yml

@@ -51,13 +51,21 @@ jobs:
 
       - name: Install dependencies
         run: |
-          pip install -q -r docs/requirements.txt
+          pip install -r docs/requirements.txt
 
       - name: Check docs for broken links
         run: |
           cd docs
           make linkcheck
 
+      - name: Install ghostscript, its fonts and latexmk
+        run: |
+          sudo apt-get update -y
+          sudo apt-get install -y ghostscript \
+                                  fonts-freefont-otf \
+                                  gsfonts
+                                  latexmk
+
       - name: Generate LaTeX code to check for errors
         run: |
           cd docs