add slack/web-api

packages/slackbot-proxy/package.json

@@ -18,6 +18,7 @@
   },
   "dependencies": {
     "@slack/oauth": "^2.0.1",
+    "@slack/web-api": "^6.1.0",
     "@tsed/common": "^6.34.3",
     "@tsed/di": "^6.34.3",
     "@tsed/platform-express": "^6.34.3",