refactor: set new expiresat on each request

[apapazisis]

PR Checklist

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

The expiresAt field is not updated while new requests are sent.

Issue Number: N/A

What is the new behavior?

The expiresAt is updated on each request. That way we always calculate a new expiration time.
As an example if I have limit:2 and ttl: minutes(1) a bot which sends multiple requests will be blocked and as long as it continues to send requests will be blocked(429 error). The rate limit should go to 2 requests per minute to release the block(429 error).

Does this PR introduce a breaking change?

• Yes
• No

Other information