Fix kustomize install: download binary, not apt package

kustomize isn't in Debian repos. Download from GitHub releases.

.gitea/workflows/deploy-preview.yaml

@@ -10,7 +10,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - run: apt-get update && apt-get install -y jq kustomize
+      - name: Install tools
+        run: |
+          apt-get update && apt-get install -y jq curl
+          curl -sL https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv5.6.0/kustomize_v5.6.0_linux_amd64.tar.gz | tar xz -C /usr/local/bin
 
       - run: corepack enable && corepack prepare pnpm@latest --activate
 

.gitea/workflows/deploy-production.yaml

@@ -12,7 +12,10 @@ jobs:
         with:
           fetch-depth: 2
 
-      - run: apt-get update && apt-get install -y jq kustomize
+      - name: Install tools
+        run: |
+          apt-get update && apt-get install -y jq curl
+          curl -sL https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv5.6.0/kustomize_v5.6.0_linux_amd64.tar.gz | tar xz -C /usr/local/bin
 
       - run: corepack enable && corepack prepare pnpm@latest --activate