public-api plugin is missed in apisix-helm-chart/charts/apisix/values.yaml

[lewiseliu]

public-api plugin is missed in apisix-helm-chart/charts/apisix/values.yaml ，which caused exception - not found. After adding the plugins by manual and rebuild the container with helm, the api can work well.

# APISIX plugins to be enabled
plugins:
- public-api

curl -X PUT 'http://127.0.0.1:9080/apisix/admin/routes/r1'
-H 'X-API-KEY: '
-H 'Content-Type: application/json'
-d '{ "uri": "/apisix/plugin/jwt/sign", "plugins": { "public-api": {} } }'

[tzssangglass]

we can try

plugins:
- public-api
- jwt-auth

?

[tokers]

I think we can submit a PR to update the default plugin list.