Update balena/open-balena-base Docker tag to v18.0.8

[balena-renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
balena/open-balena-base	stage	patch	v18.0.6 -> v18.0.8

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Release Notes

balena-io-modules/open-balena-base (balena/open-balena-base)

### [`v18.0.8`](https://togithub.com/balena-io-modules/open-balena-base/blob/HEAD/CHANGELOG.md#v1808) [Compare Source](https://togithub.com/balena-io-modules/open-balena-base/compare/v18.0.8...v18.0.8) #### (2024-07-23) - Switch to self-hosted \[Anton Belodedenko] ### [`v18.0.8`](https://togithub.com/balena-io-modules/open-balena-base/blob/HEAD/CHANGELOG.md#v1808) [Compare Source](https://togithub.com/balena-io-modules/open-balena-base/compare/v18.0.7...v18.0.8) #### (2024-07-23) - Switch to self-hosted \[Anton Belodedenko] ### [`v18.0.7`](https://togithub.com/balena-io-modules/open-balena-base/blob/HEAD/CHANGELOG.md#v1807) [Compare Source](https://togithub.com/balena-io-modules/open-balena-base/compare/v18.0.7...v18.0.7) #### (2024-07-19) - Update dependency node to v22.5.1 \[Self-hosted Renovate Bot] ### [`v18.0.7`](https://togithub.com/balena-io-modules/open-balena-base/blob/HEAD/CHANGELOG.md#v1807) [Compare Source](https://togithub.com/balena-io-modules/open-balena-base/compare/v18.0.6...v18.0.7) #### (2024-07-19) - Update dependency node to v22.5.1 \[Self-hosted Renovate Bot]

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This PR has been generated by Renovate Bot.