Add labels to entry level tasks for new contributors

[svrnm]

Hi,

based on https://github.com/open-telemetry/community/issues/469 I have added open-telemetry/opentelemetry-java-contrib to Up For Grabs:

https://up-for-grabs.net/#/filters?names=653

There are currently no issues with label help wanted. Please add this label to your entry level tasks, so people can find a way to contribute easily.

If "help wanted" is not the right label, let me know and I can change it (e.g. to "good first issue" or "up-for-grabs"), or you can provide a pull request by editing https://github.com/up-for-grabs/up-for-grabs.net/blob/gh-pages/_data/projects/opentelemetry-java-contrib.yml

Thanks!