Pin commit in github Actions

[Francois-Gomis]

Reason for change

https://linear.app/almapay/issue/ECOM-3989/security-pin-version-in-github-action-in-php-client

Seccurity request

Code changes

How to test

As a reviewer, you are encouraged to test the PR locally.

Checklist for authors and reviewers

• The title of the PR uses business wording, not technical jargon, for the changelog readers to understand it
• The PR implements the changes asked in the referenced task / issue
• The automated tests are compliant with the testing strategy
• The tests are relevant, and cover the corner/error cases, not only the happy path
• You understand the impact of this PR on existing code/features
• The changes include adequate logging and Datadog traces
• Documentation is updated (API, developer documentation, ADR, Notion...)

Non applicable

[thomas-e-alma]

=== merging with requirements not being met ===

due to the CI current state and short delays, this PR will be merged as-is.