addTags: 'template' is not recognized as a valid field

[hyangah]

Caused by missing 'template' property declaration in package.json

From v0.19.0-rc.3

[gopherbot]

Change https://golang.org/cl/273187 mentions this issue: package.json: Add "template" property to go.addTags configuration

[gopherbot]

Change https://golang.org/cl/273189 mentions this issue: [release] package.json: Add "template" property to go.addTags configuration