Update module prometheus/client_golang to v1.8.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
github.com/prometheus/client_golang	require	minor	v1.7.1 -> v1.8.0

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Release Notes

prometheus/client_golang

### [`v1.8.0`](https://togithub.com/prometheus/client_golang/releases/v1.8.0) [Compare Source](https://togithub.com/prometheus/client_golang/compare/v1.7.1...v1.8.0) - [CHANGE] API client: Use `time.Time` rather than `string` for timestamps in `RuntimeinfoResult`. [#​777](https://togithub.com/prometheus/client_golang/issues/777) - [FEATURE] Export `MetricVec` to facilitate implementation of vectors of custom `Metric` types. [#​803](https://togithub.com/prometheus/client_golang/issues/803) - \[FEATURE API client: Support `/status/tsdb` endpoint. [#​773](https://togithub.com/prometheus/client_golang/issues/773) - [ENHANCEMENT] API client: Enable GET fallback on status code 501. [#​802](https://togithub.com/prometheus/client_golang/issues/802) - [ENHANCEMENT] Remove `Metric` references after reslicing to free up more memory. [#​784](https://togithub.com/prometheus/client_golang/issues/784)

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