Update vendor (slack)

vendor/github.com/nlopes/slack/pagination.go

@@ -0,0 +1,20 @@
+package slack
+
+// Paging contains paging information
+type Paging struct {
+	Count int `json:"count"`
+	Total int `json:"total"`
+	Page  int `json:"page"`
+	Pages int `json:"pages"`
+}
+
+// Pagination contains pagination information
+// This is different from Paging in that it contains additional details
+type Pagination struct {
+	TotalCount int `json:"total_count"`
+	Page       int `json:"page"`
+	PerPage    int `json:"per_page"`
+	PageCount  int `json:"page_count"`
+	First      int `json:"first"`
+	Last       int `json:"last"`
+}