Add missing build-dependency

Author: ehrenfeu

.github/workflows/build.yml

@@ -57,6 +57,12 @@ jobs:
     - uses: actions/checkout@v4
       name: 📥 Checkout repo
 
+    - name: 🗃 Cache 📦 APT Packages
+      uses: awalsh128/cache-apt-pkgs-action@v1.4.3
+      with:
+        packages: xmlstarlet
+        version: 1.0
+
     - name: 🕵 Inspect if this is a proper "scijava-scripts" release
       run: scripts/check-if-release.sh