chore: Update examples link during release process

[AgustinBettati]

Description

Link to any related issue(s): CLOUDP-238066

Adds new step in release workflow to update how we reference the examples section from our terraform index page documentation.

Testing

• Executed different scenarios of releases making sure both commits of the release process are done correctly: release action, new commit being made, commits in master branch.

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contributing guides
• I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals, I defined an isolated PR with a relevant title as it will be used in the auto-generated changelog.
• If changes include removal or addition of 3rd party GitHub actions, I updated our internal document. Reach out to the APIx Integration slack channel to get access to the internal document.

Further comments

[AgustinBettati]

extracted this as it will also contain logic for commit signing and configuring github PAT.

[EspenAlbert]

[nit] Curious why we are not using "in-place" (-I flag)?

[AgustinBettati]

Went for this approach initially but the implementation of sed in macOS vs Linux handles the -i parameter differently. Opted for having same behaviour in CI vs running locally by simplifying how the command is invoked.

[EspenAlbert]

LGMT 👍