:+1: version and update docs

CHANGES.md

@@ -1,12 +1,18 @@
 # CHANGES
 
-## v4.2.18-RC
+## v4.2.19-RC
+
+* 
+
+## v4.2.18
 
 * Feature: Cobvertible page contents width.
 * Fix: Group selector of User Group Delete Modal does not show all groups
 * Fix: Global notification to Slack does not encode spaces of page path
 * Support: Upgrade libs
     * @google-cloud/storage
+    * @slack/web-api
+    * @slack/webhook
 
 ## v4.2.17
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "growi",
-  "version": "4.2.18-RC",
+  "version": "4.2.19-RC",
   "description": "Team collaboration software using markdown",
   "tags": [
     "wiki",