Google cloud storage return old images

I have a public bucket, uploading the images through a React web app using a signed url:

export const uploadFile = (policy: PostPolicy, file: File): Promise<void> => {
  const formData = new FormData();

  for (const field in policy.fields) {
    const value = policy.fields[field];
    value && formData.append(field, value);
  }
  formData.append("file", file);

  return fetch(policy.url, {
    method: "POST",
    body: formData,
  }).then();
};

The PostPolicy is the result of the call to bucket.GenerateSignedPostPolicyV4. The upload and retrieving work, but once the image is updated, the browser seems to cache the old file, for a long time, and I am not able to edit this caching. I already tried´to user the gcloud-cors-settings adding maxAgeSeconds:

[
  {
    "maxAgeSeconds": 10,
    "method": ["POST", "GET"],
    "origin": ["http://localhost:50030"],
    "responseHeader": ["Content-Type", "Cache-Control"]
  }
]

Did not help. I tried to add the ‘Cache-Control’ header:

export const uploadFile = (policy: PostPolicy, file: File): Promise<void> => {
  const formData = new FormData();

  for (const field in policy.fields) {
    const value = policy.fields[field];
    value && formData.append(field, value);
  }
  formData.append("file", file);

  const headers = new Headers();
  headers.append("Cache-Control", "public, max-age=15");

  return fetch(policy.url, {
    method: "POST",
    headers: headers,
    body: formData,
  }).then();
};

I don’t get any error, but the header is ignored.

How can I fix this problem?