chore(deps): bump github.com/slack-go/slack from 0.12.3 to 0.12.4

Bumps [github.com/slack-go/slack](https://github.com/slack-go/slack) from 0.12.3 to 0.12.4.
- [Release notes](https://github.com/slack-go/slack/releases)
- [Changelog](https://github.com/slack-go/slack/blob/master/CHANGELOG.md)
- [Commits](slack-go/slack@v0.12.3...v0.12.4)

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

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

Author: dependabot[bot]

go.mod

@@ -9,7 +9,7 @@ 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 v0.12.3
+	github.com/slack-go/slack v0.12.4
 	golang.org/x/oauth2 v0.17.0
 	gopkg.in/errgo.v2 v2.1.0
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -957,8 +957,8 @@ github.com/sirupsen/logrus v1.4.1/go.mod h1:ni0Sbl8bgC9z8RoU9G6nDWqqs/fq4eDPysMB
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 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 v0.12.3 h1:92/dfFU8Q5XP6Wp5rr5/T5JHLM5c5Smtn53fhToAP88=
-github.com/slack-go/slack v0.12.3/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/slack-go/slack v0.12.4 h1:4iLT2opw+/QptmQxBNA7S8pNfSIvtn0NDGu7Jq0emi4=
+github.com/slack-go/slack v0.12.4/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/spf13/afero v1.3.3/go.mod h1:5KUK8ByomD5Ti5Artl0RtHeI5pTF7MIDuXL3yY520V4=
 github.com/spf13/afero v1.6.0/go.mod h1:Ai8FlHk4v/PARR026UzYexafAt9roJ7LcLMAmO6Z93I=