Small fixes for google-genai before releasing

[aabmass]

Description

• Change version to 0.1b0.dev to match the rest of contrib. The first release will then be 0.1b0.
• Add to the independent release workflows and README.md

cc @michaelsafyan

Type of change

Please delete options that are not relevant.

• tooling

How Has This Been Tested?

I also checked the dists

$ uvx twine check dist/*
Checking dist/opentelemetry_instrumentation_google_genai-0.1b0.dev0-py3-none-any.whl: PASSED
Checking dist/opentelemetry_instrumentation_google_genai-0.1b0.dev0.tar.gz: PASSED

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[michaelsafyan]

LGTM