ci: update shellcheck installation method in CI config

.forgejo/workflows/ci.yml

@@ -13,10 +13,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      
+
       - name: Install shellcheck
-        run: sudo apt-get install -y shellcheck
-      
+        run: |
+          wget https://github.com/koalaman/shellcheck/releases/download/v0.9.4/shellcheck_0.9.4-1_amd64.deb
+          sudo apt-get install -y ./shellcheck_0.9.4-1_amd64.deb
+          rm shellcheck_0.9.4-1_amd64.deb
+
       - name: Lint bash scripts
         run: |
-          find . -type f -name "*.sh" -exec shellcheck {} \;
+          find . -type f -name "*.sh" -print0 | xargs -0 shellcheck