CI: install git + ca-certificates before checkout (debian:bookworm ships neither)

.gitea/workflows/build.yml

@@ -7,10 +7,11 @@ jobs:
     container: debian:bookworm
     timeout-minutes: 10
     steps:
+      - name: Install git + lua (bookworm base image ships neither)
+        run: apt-get update -qq && apt-get install -y -qq git ca-certificates lua5.4
+
       - name: Checkout
         run: git clone --depth 1 ${{ github.server_url }}/${{ github.repository }}.git .
 
       - name: Lua syntax check
-        run: |
-          apt-get update -qq && apt-get install -y -qq lua5.4
-          find . -name '*.lua' -not -path './.git/*' -print0 | xargs -0 -n1 luac5.4 -p
+        run: find . -name '*.lua' -not -path './.git/*' -print0 | xargs -0 -n1 luac5.4 -p