fix(.pre-commit-config.yaml): fix hook id to match actual name

[Paillat-dev]

:hammer_and_wrench: Description

.pre-comit-config.yaml, for some reason referred to a hook (copywrite-headers) which was not described in .pre-commit-hooks.yaml. I have no idea why this was the case, but changed it to make use of the add-headers hook which is in fact defined.

:link: External Links

:+1: Definition of Done

• [x] New functionality works?
• [ ] Tests added?

:thinking: Can be merged upon approval?

:white_check_mark:

[hashicorp-cla-app[bot]]

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