Add google-apis-bigquery_v2 gems rbs signatures

[euglena1215]

and, some other gems rbs signatures.

• google-apis-core
• googleauth
• signet

[github-actions]

@euglena1215 Thanks for your contribution!

Please follow the instructions below for each change.
See also: https://github.com/ruby/gem_rbs_collection/blob/main/docs/CONTRIBUTING.md

Available commands

You can use the following commands by commenting on this PR.

• /merge: Merge this PR if CI passes

---

google-apis-bigquery_v2

This RBS files are newly added.

You can merge this PR immediately if the CI passes.
Just comment /merge to merge this PR.

---

google-apis-core

This RBS files are newly added.

You can merge this PR immediately if the CI passes.
Just comment /merge to merge this PR.

---

googleauth

You changed RBS files for an existing gem.
This gem does not have reviewers. So you can merge this PR immediately if the CI passes.
We recommend you add yourself to the reviewers for this gem.

---

signet

You changed RBS files for an existing gem.
This gem does not have reviewers. So you can merge this PR immediately if the CI passes.
We recommend you add yourself to the reviewers for this gem.

[euglena1215]

/merge