AppId not set when using Helm chart

I tried to deploy Safe-settings on an EKS cluster by using the Helm chart 0.1.0.

```
helm upgrade --install \
--username="XXX" \
--password="XXX" \
safe-settings-test \
-f values.yml \
--set appEnv.APP_ID="\"XXX\"" \
--set appEnv.PRIVATE_KEY="XXX" \
--set appEnv.WEBHOOK_SECRET="XXX" \
--set appEnv.DEPLOYMENT_CONFIG_FILE="deployment-settings.yml" \
--namespace YYY \
https://enterprise-repo/safe-settings-0.1.0.tgz
```

(using XXX for obfuscation)

We got the following error :

> safe-settings@0.1.0-rc.26 start /opt/safe-settings
> probot run ./index.js

(node:36) UnhandledPromiseRejectionWarning: Error: [@octokit/auth-app] appId option is required
at Object.createAppAuth (/opt/safe-settings/node_modules/@octokit/auth-app/dist-node/index.js:402:11)
at getState (/opt/safe-settings/node_modules/octokit-auth-probot/dist-node/index.js:176:21)
at createProbotAuth (/opt/safe-settings/node_modules/octokit-auth-probot/dist-node/index.js:191:17)
at new Octokit (/opt/safe-settings/node_modules/@octokit/core/dist-node/index.js:113:20)
at new _a (/opt/safe-settings/node_modules/@octokit/core/dist-node/index.js:167:30)
at new OctokitWithDefaults (/opt/safe-settings/node_modules/@octokit/core/dist-node/index.js:143:11)
at new OctokitWithDefaults (/opt/safe-settings/node_modules/@octokit/core/dist-node/index.js:143:11)
at new Probot (/opt/safe-settings/node_modules/probot/lib/probot.js:38:25)
at new ProbotWithDefaults (/opt/safe-settings/node_modules/probot/lib/probot.js:64:17)
at new Server (/opt/safe-settings/node_modules/probot/lib/server/server.js:36:26)
(Use `node --trace-warnings ...` to show where the warning was created)

I realized that the default docker image version is the 2.0.0 and gave also a try with the 2.0.18, but got the same issue.

It seems that the options are not correctly set but I can clearly see that my pod has the following environments variables : APP_ID, WEBHOOK_SECRET and PRIVATE_KEY with the expected values as defined during helm command execution.

Definitely need some help toe troubleshoot this issue :-)