Bump github.com/slack-go/slack from v0.23.0 to v0.23.1

[dghubble-renovate]

This PR contains the following updates:

Package	Type	Update	Change
github.com/slack-go/slack	require	patch	v0.23.0 → v0.23.1

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Release Notes

slack-go/slack (github.com/slack-go/slack)

v0.23.1

Compare Source

[!IMPORTANT]
Even though this is a [security] patch release, if you were using an empty secret, this is a breaking change due to a change in behaviour. That's on purpose, to ensure you fix your approach so that there are no footguns.

Fixed

• NewSecretsVerifier now rejects empty signing secrets to avoid accepting forged request
  signatures when applications are misconfigured.

Full Changelog: slack-go/slack@v0.23.0...v0.23.1

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