workflow: attempt to fix AllenDang#2

use diffrent just installation method

Author: gucio321

.github/workflows/update_submodules.yaml

@@ -12,9 +12,10 @@ jobs:
     steps:
       - name: install JUST
         run:
-          git clone 'https://mpr.makedeb.org/just'
-          cd just
-          makedeb -sl
+          curl -q 'https://proget.makedeb.org/debian-feeds/prebuilt-mpr.pub' | gpg --dearmor | sudo tee /usr/share/keyrings/prebuilt-mpr-archive-keyring.gpg 1> /dev/null
+          echo "deb [signed-by=/usr/share/keyrings/prebuilt-mpr-archive-keyring.gpg] https://proget.makedeb.org prebuilt-mpr $(lsb_release -cs)" | sudo tee /etc/apt/sources.list.d/prebuilt-mpr.list
+          sudo apt update
+          sudo apt install just
       - name: Set up LibGL, Mesa & X11 libraries
         run: |
           sudo apt-get --allow-releaseinfo-change update