Update SQL Agent extension readme and version (#1343)

extensions/agent/package.json

@@ -2,7 +2,7 @@
   "name": "agent",
   "displayName": "SQL Server Agent",
   "description": "Manage and troubleshoot SQL Server Agent jobs (early preview)",
-  "version": "0.28.1",
+  "version": "0.29.0",
   "publisher": "Microsoft",
   "preview": true,
   "license": "https://raw.githubusercontent.com/Microsoft/sqlopsstudio/master/LICENSE.txt",
@@ -22,6 +22,9 @@
     "type": "git",
     "url": "https://github.com/Microsoft/sqlopsstudio.git"
   },
+  "extensionDependencies": [
+    "Microsoft.mssql"
+  ],
   "contributes": {
     "outputChannels": [
       "sqlagent"