feat: add util file to base64

src/utils/file.ts

@@ -0,0 +1,8 @@
+export function fileToBase64(file: File) {
+  return new Promise<string>((resolve, reject) => {
+    const reader = new FileReader();
+    reader.addEventListener('error', reject);
+    reader.addEventListener('load', () => resolve(reader.result as string));
+    reader.readAsDataURL(file);
+  });
+}