chore(deps): bump github.com/slack-go/slack from 0.14.0 to 0.15.0 (#2769)

Bumps [github.com/slack-go/slack](https://github.com/slack-go/slack) from 0.14.0 to 0.15.0.
- [Release notes](https://github.com/slack-go/slack/releases)
- [Changelog](https://github.com/slack-go/slack/blob/master/CHANGELOG.md)
- [Commits](slack-go/slack@v0.14.0...v0.15.0)

---
updated-dependencies:
- dependency-name: github.com/slack-go/slack
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

go.mod

@@ -40,7 +40,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/muesli/reflow v0.3.0
 	github.com/oapi-codegen/runtime v1.1.1
-	github.com/slack-go/slack v0.14.0
+	github.com/slack-go/slack v0.15.0
 	github.com/spf13/afero v1.11.0
 	github.com/spf13/cobra v1.8.1
 	github.com/spf13/pflag v1.0.5

go.sum

@@ -900,8 +900,8 @@ github.com/sivchari/tenv v1.7.1 h1:PSpuD4bu6fSmtWMxSGWcvqUUgIn7k3yOJhOIzVWn8Ak=
 github.com/sivchari/tenv v1.7.1/go.mod h1:64yStXKSOxDfX47NlhVwND4dHwfZDdbp2Lyl018Icvg=
 github.com/skeema/knownhosts v1.2.2 h1:Iug2P4fLmDw9f41PB6thxUkNUkJzB5i+1/exaj40L3A=
 github.com/skeema/knownhosts v1.2.2/go.mod h1:xYbVRSPxqBZFrdmDyMmsOs+uX1UZC3nTN3ThzgDxUwo=
-github.com/slack-go/slack v0.14.0 h1:6c0UTfbRnvRssZUsZ2qe0Iu07VAMPjRqOa6oX8ewF4k=
-github.com/slack-go/slack v0.14.0/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/slack-go/slack v0.15.0 h1:LE2lj2y9vqqiOf+qIIy0GvEoxgF1N5yLGZffmEZykt0=
+github.com/slack-go/slack v0.15.0/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
 github.com/sonatard/noctx v0.0.2 h1:L7Dz4De2zDQhW8S0t+KUjY0MAQJd6SgVwhzNIc4ok00=
 github.com/sonatard/noctx v0.0.2/go.mod h1:kzFz+CzWSjQ2OzIm46uJZoXuBpa2+0y3T36U18dWqIo=
 github.com/sourcegraph/conc v0.3.0 h1:OQTbbt6P72L20UqAkXXuLOj79LfEanQ+YQFNpLA9ySo=