Retry ignores limit response headers when hourly API rate limit is reached

[matejlukac]

Terraform fastly provider is not utilizing fastly limitation response headers when executing non-read requests.
https://developer.fastly.com/reference/api/#rate-limiting.

Rate limit information is provided in response headers, as shown below. The Fastly-RateLimit-Remaining header provides the number of API requests remaining in the current rate limit window. The Fastly-RateLimit-Reset provides the time at which the current rate limit window resets, as a Unix timestamp.

Fastly-RateLimit-Remaining: 999
Fastly-RateLimit-Reset: 1452032384

Terraform Version

v0.12.17

Expected Behavior

Terraform should retry non-read requests after the time specified in fastly response header when API rate limit is reached.

Actual Behavior

Error is thrown after API rate limit is reached.
Error: 429 - Too Many Requests:
Title: You have exceeded your hourly rate limit. Please contact [email protected] if you think this is a mistake.

Steps to Reproduce

Execute the number of non-read requests larger than hourly rate limit.