Not able to add supportedHosts property in spfx webpart manifest file

I wanted to deploy an spfx webpart as a tab in MS teams. I have created an spfx webpart and tried to insert "supportedHosts: TeamsTab"property in webpart manifest file but it is giving me an error while running gulp serve.  

Error:

[16:20:39] Error - [write-manifests] Manifest validation error (./src/webparts/myFirstTeamTab/MyFirstTeamTabWebPart.manifest.json): (#/) Data does not match any schemas from 'oneOf' (#/) Missing required property: description (#/) Missing required property: extensionType (#/componentType) No enum match for: WebPart (#/) Additional properties not allowed: supportedHosts (#/) Missing required property: items (#/) Missing required property: rootComponentId

I am not able to find out what is the actual cause?

Spfx version-1.11.0

Node-12.18.0