update checkout action

Trying to fix this error:

    Missing download info for actions/upload-artifact@v3

Author: garfieldnate

.github/workflows/build.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v4
 
       - name: install system dependencies
         run: sudo apt-get update && sudo apt-get install pandoc texlive-latex-base texlive-fonts-recommended texlive-fonts-extra texlive-latex-extra