fix: update references to ghcr.io/renovatebot/renovate to v39.15.3

[renovate[bot]]

This PR contains the following updates:

Package	Update	Change
ghcr.io/renovatebot/renovate (source)	patch	39.15.2 -> 39.15.3

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Release Notes

renovatebot/renovate (ghcr.io/renovatebot/renovate)

### [`v39.15.3`](https://redirect.github.com/renovatebot/renovate/compare/39.15.2...6c75b77ecd4ee1089d022650e05ddbcf28af8b37) [Compare Source](https://redirect.github.com/renovatebot/renovate/compare/39.15.2...39.15.3)

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