chore(deps): update dependency open-feature/test-harness to v0.5.4

[renovate[bot]]

This PR contains the following updates:

Package	Update	Change
open-feature/test-harness	patch	v0.5.2 -> v0.5.4

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Release Notes

open-feature/test-harness (open-feature/test-harness)

### [`v0.5.4`](https://togithub.com/open-feature/flagd-testbed/releases/tag/v0.5.4) [Compare Source](https://togithub.com/open-feature/test-harness/compare/v0.5.3...v0.5.4) ##### Features - bump flagd to new release ([#​118](https://togithub.com/open-feature/flagd-testbed/issues/118)) ([def1f0b](https://togithub.com/open-feature/flagd-testbed/commit/def1f0b2f486c8dbb23aa98ccc3b2672bf42cb0a)) ### [`v0.5.3`](https://togithub.com/open-feature/flagd-testbed/releases/tag/v0.5.3) [Compare Source](https://togithub.com/open-feature/test-harness/compare/v0.5.2...v0.5.3) ##### Features - test multiple fractional flags with shared seed ([#​115](https://togithub.com/open-feature/flagd-testbed/issues/115)) ([25544e4](https://togithub.com/open-feature/flagd-testbed/commit/25544e43d65500ea085d6f0e242b9a616a51f776)) ##### Bug Fixes - **deps:** update golang.org/x/exp digest to [`a685a6e`](https://togithub.com/open-feature/test-harness/commit/a685a6e) ([#​113](https://togithub.com/open-feature/flagd-testbed/issues/113)) ([620df72](https://togithub.com/open-feature/flagd-testbed/commit/620df72fe2982004ffe9c3e9798de95e92178084))

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