Update module github.com/prometheus/client_golang to v1.20.3

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
github.com/prometheus/client_golang	v1.20.2 -> v1.20.3

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Release Notes

prometheus/client_golang (github.com/prometheus/client_golang)

### [`v1.20.3`](https://redirect.github.com/prometheus/client_golang/releases/tag/v1.20.3) [Compare Source](https://redirect.github.com/prometheus/client_golang/compare/v1.20.2...v1.20.3) - \[BUGFIX] histograms: Fix possible data race when appending exemplars. [#​1608](https://redirect.github.com/prometheus/client_golang/issues/1608)

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