OIDC GCP docs: fix link

[ulfjack]

Why: fix link that's supposed to link to GCP's OIDC documentation

Closes:

What's being changed (if available, include any code snippets, screenshots, or gifs): documentation

Check off the following:

• I have reviewed my changes in staging, available via the View deployment link in this PR's timeline (this link will be available after opening the PR).

  • For content changes, you will also see an automatically generated comment with links directly to pages you've modified. The comment won't appear if your PR only edits files in the data directory.

• For content changes, I have completed the self-review checklist.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[github-actions]

👋 Hey there spelunker. It looks like you've modified some files that we can't accept as contributions:

• content/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-google-cloud-platform.md

You'll need to revert all of the files you changed that match that list using GitHub Desktop or git checkout origin/main <file name>. Once you get those files reverted, we can continue with the review process.

The complete list of files we can't accept are:

• .devcontainer/**
• .github/workflows/**
• .github/CODEOWNERS
• assets/fonts/**
• data/graphql/**
• data/reusables/rai/**
• Dockerfile*
• src/*/scripts/**
• src/**.json
• src/workflows/**
• lib/redirects/**
• package*.json
• content/actions/deployment/security-hardening-your-deployments/**

We also can't accept contributions to files in the content directory with frontmatter type: rai.