Update broken links

[HonkingGoose]

Edit: I'm not allowed to make the changes, so I created an issue instead:

• Update broken links to v1 version of ProGit book #25653

---

Why:

There are some links to point to v1 of the ProGit book on the git-scm.com site. The v1 version of those links lead to a server error page.

Closes: I've not created an issue.

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

Replacing v1 with v2 in the URL makes the link lead to the correct page again.

Check off the following:

• I have reviewed my changes in staging, available via the View deployment link in this PR's timeline.

  • 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.

[github-actions]

👋 Hey there spelunker. It looks like you've modified some files that we can't accept as contributions. The complete list of files we can't accept are:
.devcontainer/**
.github/actions-scripts/**
.github/workflows/**
.github/CODEOWNERS
assets/fonts/**
data/graphql/**
Dockerfile*
src/**
lib/redirects/**
package*.json
scripts/**
content/actions/deployment/security-hardening-your-deployments/**

You'll need to revert all of the files you changed in 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.