Add Organization-level public key data sources

[bodgit]

Add the following new data sources:

• github_actions_organization_public_key
• github_dependabot_organization_public_key

Resolves #1607

---

Additional info

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Added the appropriate label for the given change

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes (Please add the Type: Breaking change label)
• No

If Yes, what's the impact:

• N/A

Pull request type

Please add the corresponding label for change this PR introduces:

• Bugfix: Type: Bug
• Feature/model/API additions: Type: Feature
• Updates to docs or samples: Type: Documentation
• Dependencies/code cleanup: Type: Maintenance

---

[bodgit]

$ TF_ACC=1 go test -v ./... -run ^TestAccGithub.*OrganizationPublicKeyDataSource
?       github.com/integrations/terraform-provider-github/v5    [no test files]
=== RUN   TestAccGithubActionsOrganizationPublicKeyDataSource
=== RUN   TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error
=== RUN   TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_anonymous_account
    data_source_github_actions_organization_public_key_test.go:37: anonymous account not supported for this operation
=== RUN   TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_individual_account
    data_source_github_actions_organization_public_key_test.go:41: individual account not supported for this operation
=== RUN   TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_organization_account
--- PASS: TestAccGithubActionsOrganizationPublicKeyDataSource (2.94s)
    --- PASS: TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error (2.94s)
        --- SKIP: TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_anonymous_account (0.00s)
        --- SKIP: TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_individual_account (0.00s)
        --- PASS: TestAccGithubActionsOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_organization_account (2.94s)
=== RUN   TestAccGithubDependabotOrganizationPublicKeyDataSource
=== RUN   TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error
=== RUN   TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_anonymous_account
    data_source_github_dependabot_organization_public_key_test.go:37: anonymous account not supported for this operation
=== RUN   TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_individual_account
    data_source_github_dependabot_organization_public_key_test.go:41: individual account not supported for this operation
=== RUN   TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_organization_account
--- PASS: TestAccGithubDependabotOrganizationPublicKeyDataSource (2.84s)
    --- PASS: TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error (2.84s)
        --- SKIP: TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_anonymous_account (0.00s)
        --- SKIP: TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_individual_account (0.00s)
        --- PASS: TestAccGithubDependabotOrganizationPublicKeyDataSource/queries_an_organization_public_key_without_error/with_an_organization_account (2.84s)
PASS
ok      github.com/integrations/terraform-provider-github/v5/github     (cached)

[kfcampbell]

Confirming that the newly-added integration tests are passing for me. Thank you for contributing!