fix(deps): update module github.com/slack-go/slack to v0.12.4

go.mod

@@ -5,5 +5,5 @@ go 1.15
 require (
 	github.com/google/uuid v1.3.0
 	github.com/humsie/log v1.3.1
-	github.com/slack-go/slack v0.10.1
+	github.com/slack-go/slack v0.12.4
 )

go.sum

@@ -1,5 +1,6 @@
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/google/uuid v1.2.0 h1:qJYtXnJRWmpe7m/3XlyhrsLrEURqHRM2kxzoxXqyUDs=
 github.com/google/uuid v1.2.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
@@ -15,4 +16,7 @@ github.com/slack-go/slack v0.9.1 h1:pekQBs0RmrdAgoqzcMCzUCWSyIkhzUU3F83ExAdZrKo=
 github.com/slack-go/slack v0.9.1/go.mod h1:wWL//kk0ho+FcQXcBTmEafUI5dz4qz5f4mMk8oIkioQ=
 github.com/slack-go/slack v0.10.1 h1:BGbxa0kMsGEvLOEoZmYs8T1wWfoZXwmQFBb6FgYCXUA=
 github.com/slack-go/slack v0.10.1/go.mod h1:wWL//kk0ho+FcQXcBTmEafUI5dz4qz5f4mMk8oIkioQ=
+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/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=