fix(deps): update module github.com/slack-go/slack to v0.15.0

go.mod

@@ -15,7 +15,7 @@ require (
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/sdming/gosnow v0.0.0-20130403030620-3a05c415e886 // indirect
 	github.com/sirupsen/logrus v1.8.1
-	github.com/slack-go/slack v0.10.2
+	github.com/slack-go/slack v0.15.0
 	github.com/spf13/viper v1.10.1
 	golang.org/x/exp v0.0.0-20201221025956-e89b829e73ea // indirect
 	google.golang.org/genproto v0.0.0-20220307174427-659dce7fcb03

go.sum

@@ -413,6 +413,8 @@ github.com/slack-go/slack v0.9.4 h1:C+FC3zLxLxUTQjDy2RZeMHYon005zsCROiZNWVo+opQ=
 github.com/slack-go/slack v0.9.4/go.mod h1:wWL//kk0ho+FcQXcBTmEafUI5dz4qz5f4mMk8oIkioQ=
 github.com/slack-go/slack v0.10.2 h1:KMN/h2sgUninHXvQI8PrR/PHBUuWp2NPvz2Kr66tki4=
 github.com/slack-go/slack v0.10.2/go.mod h1:5FLdBRv7VW/d9EBxx/eEktOptWygbA9K2QK/KW7ds1s=
+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/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
 github.com/smartystreets/goconvey v1.6.4/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA=
 github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=