Resource detection package for Heroku

[sjparkinson]

Is your feature request related to a problem? Please describe

We run Node.js services on the Heroku platform and would like to use a resource detection package to configure the relevant Heroku resource attributes.

Describe the solution you'd like to see

A new opentelemetry-resource-detector-heroku package is available that utilises the Heroku dyno and build metadata environment variables.

Describe alternatives you've considered

We currently manually configure the Heroku resource attributes using these environment variables in each app.

Additional context

• https://devcenter.heroku.com/articles/dyno-metadata
• https://opentelemetry.io/docs/specs/semconv/resource/cloud-provider/heroku/

[sjparkinson]

One resource attribute that will be hard to detect within Heroku is the cloud.region. As far as I am aware there isn't an environment variable available with that detail.