Update preview.yml

fix preview bug on setting up dependencies

Author: loumir

.github/workflows/preview.yml

@@ -30,6 +30,7 @@ jobs:
 
     - name: Setup dependencies
       run: |
+        sudo apt update
         sudo apt install texlive-latex-base texlive-latex-recommended \
                          texlive-latex-extra texlive-fonts-recommended \
                          librsvg2-bin latexmk \