Bump github.com/slack-go/slack from 0.18.0 to 0.19.0

Bumps [github.com/slack-go/slack](https://github.com/slack-go/slack) from 0.18.0 to 0.19.0.
- [Release notes](https://github.com/slack-go/slack/releases)
- [Changelog](https://github.com/slack-go/slack/blob/master/CHANGELOG.md)
- [Commits](slack-go/slack@v0.18.0...v0.19.0)

---
updated-dependencies:
- dependency-name: github.com/slack-go/slack
  dependency-version: 0.19.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/nikoksr/notify v0.41.1
 	github.com/robertkrimen/otto v0.5.1
 	github.com/robfig/cron/v3 v3.0.1
-	github.com/slack-go/slack v0.18.0
+	github.com/slack-go/slack v0.19.0
 	github.com/stretchr/testify v1.11.1
 	gopkg.in/yaml.v2 v2.4.0
 )

go.sum

@@ -104,8 +104,8 @@ github.com/sergeymakinen/go-bmp v1.0.0/go.mod h1:/mxlAQZRLxSvJFNIEGGLBE/m40f3ZnU
 github.com/sergeymakinen/go-ico v1.0.0-beta.0 h1:m5qKH7uPKLdrygMWxbamVn+tl2HfiA3K6MFJw4GfZvQ=
 github.com/sergeymakinen/go-ico v1.0.0-beta.0/go.mod h1:wQ47mTczswBO5F0NoDt7O0IXgnV4Xy3ojrroMQzyhUk=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
-github.com/slack-go/slack v0.18.0 h1:PM3IWgAoaPTnitOyfy8Unq/rk8OZLAxlBUhNLv8sbyg=
-github.com/slack-go/slack v0.18.0/go.mod h1:K81UmCivcYd/5Jmz8vLBfuyoZ3B4rQC2GHVXHteXiAE=
+github.com/slack-go/slack v0.19.0 h1:J8lL/nGTsIUX53HU8YxZeI3PDkA+sxZsFrI2Dew7h44=
+github.com/slack-go/slack v0.19.0/go.mod h1:K81UmCivcYd/5Jmz8vLBfuyoZ3B4rQC2GHVXHteXiAE=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=