Fix cloudflare_api_token's modified_on field

[danopia]

For some reason this field was always set to time.Now() when reading, which shows as drift in every Terraform plan:

Terraform detected the following changes made outside of Terraform since the
last "terraform apply":

  # cloudflare_api_token.external-dns has changed
  ~ resource "cloudflare_api_token" "external-dns" {
        id          = "[redacted]"
      ~ modified_on = "2021-11-05T09:23:00.921389278Z" -> "2022-01-04T14:35:50.581109737Z"
        name        = "external dns"
        # (3 unchanged attributes hidden)

        # (1 unchanged block hidden)
    }

It's always shown as the exact time of the plan, which is definitely not when every token was last modified!

It looks like the swap happened within the PR adding this resource: 02bb4db so as an outsider I don't have an explanation for why time.Now() was inserted.

[jacobbednarz]

thanks for the PR! this needs a CHANGELOG entry added before we can merge this.

[danopia]

I added a changelog, looks like they want to be one line otherwise I would've mentioned how it fixes Objects have changed outside of Terraform messages.

I also took the time to figure out how to use a custom provider build locally, and this patch does actually work & resolve the issue :)

[jacobbednarz]

thank you! i'm really glad you took the time to go through those steps and got a better understanding of how this all works together 😄