fix: Add nixpacks configuration for Astro deployment

dealplustech-astro/node_modules/micromark-extension-gfm-strikethrough/lib/syntax.d.ts

@@ -0,0 +1,12 @@
+/**
+ * Create an extension for `micromark` to enable GFM strikethrough syntax.
+ *
+ * @param {Options | null | undefined} [options={}]
+ *   Configuration.
+ * @returns {Extension}
+ *   Extension for `micromark` that can be passed in `extensions`, to
+ *   enable GFM strikethrough syntax.
+ */
+export function gfmStrikethrough(options?: Options | null | undefined): Extension;
+import type { Options } from 'micromark-extension-gfm-strikethrough';
+import type { Extension } from 'micromark-util-types';