chore(deps): bump github.com/slack-go/slack from 0.12.5 to 0.13.0

Bumps [github.com/slack-go/slack](https://github.com/slack-go/slack) from 0.12.5 to 0.13.0.
- [Release notes](https://github.com/slack-go/slack/releases)
- [Changelog](https://github.com/slack-go/slack/blob/master/CHANGELOG.md)
- [Commits](slack-go/slack@v0.12.5...v0.13.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/pkg/errors v0.9.1
 	github.com/sirupsen/logrus v1.9.3
-	github.com/slack-go/slack v0.12.5
+	github.com/slack-go/slack v0.13.0
 	golang.org/x/oauth2 v0.20.0
 	gopkg.in/errgo.v2 v2.1.0
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -69,8 +69,8 @@ github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDN
 github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
-github.com/slack-go/slack v0.12.5 h1:ddZ6uz6XVaB+3MTDhoW04gG+Vc/M/X1ctC+wssy2cqs=
-github.com/slack-go/slack v0.12.5/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/slack-go/slack v0.13.0 h1:7my/pR2ubZJ9912p9FtvALYpbt0cQPAqkRy2jaSI1PQ=
+github.com/slack-go/slack v0.13.0/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=