Add the `pre-commit` ecosystem to Dependabot

[jbampton]

Keeps the hooks up to date

https://github.com/apache/cloudstack/blob/main/.github/dependabot.yml

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https://docs.github.com/en/code-security/reference/supply-chain-security/supported-ecosystems-and-repositories#supported-ecosystems-maintained-by-github

Used on other ASF projects:

https://github.com/apache/sedona/blob/fe3968619a67e0f51e567ca7cdf2b67b7595d1ee/.github/dependabot.yml#L44

https://github.com/apache/lucenenet/blob/2043209be7859e1f763dc5a3c085fcfcd00dbcbd/.github/dependabot.yml#L20

refs apache/shiro#2883