fix: Add nixpacks configuration for Astro deployment

dealplustech-astro/node_modules/csso/lib/replace/Atrule.js

@@ -0,0 +1,9 @@
+import { keyword as resolveKeyword } from 'css-tree';
+import compressKeyframes from './atrule/keyframes.js';
+
+export default function(node) {
+    // compress @keyframe selectors
+    if (resolveKeyword(node.name).basename === 'keyframes') {
+        compressKeyframes(node);
+    }
+};