fix(cicd): Add google cloud sdk installation (#613)

# Description
It seems like the latest version of the Ubuntu image used in our GitHub
runners [no longer
contain](actions/runner-images#10636) the
Google Cloud CLI/SDK preinstalled (this has been removed amongst other
CLI tools 'due to maintenance reasons') and this change now breaks one
of our CICD workflows where we're expecting it to be installed.

This PR simply adds another step in the affected CICD workflow to
install the CLI/SDK explicitly (see
https://github.com/stackrox/stackrox/pull/12968/files for an example).

Compare the Ubuntu images used to run the same CICD workflow here:
Attempt 1 (version 20240922.1.0) [SUCCESS]:

https://github.com/caraml-dev/merlin/actions/runs/11232637125/job/31224653961#step:1:9

Attempt 2 (version 20241006.1.0) [FAILURE]:

https://github.com/caraml-dev/merlin/actions/runs/11232637125/job/31335777735#step:1:9

# Modifications
- Addition of a new step in the batch predictor unit test CICD workflow

# Tests
<!-- Besides the existing / updated automated tests, what specific
scenarios should be tested? Consider the backward compatibility of the
changes, whether corner cases are covered, etc. Please describe the
tests and check the ones that have been completed. Eg:
- [x] Deploying new and existing standard models
- [ ] Deploying PyFunc models
-->

# Checklist
- [x] Added PR label
- [ ] Added unit test, integration, and/or e2e tests
- [ ] Tested locally
- [ ] Updated documentation
- [ ] Update Swagger spec if the PR introduce API changes
- [ ] Regenerated Golang and Python client if the PR introduces API
changes

# Release Notes
<!--
Does this PR introduce a user-facing change?
If no, just write "NONE" in the release-note block below.
If yes, a release note is required. Enter your extended release note in
the block below.
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```release-note
NONE
```

.github/workflows/merlin.yml

@@ -48,6 +48,8 @@ jobs:
       PIPENV_DEFAULT_PYTHON_VERSION: ${{ matrix.python-version }}
     steps:
       - uses: actions/checkout@v4
+      - name: Set up Google Cloud SDK
+        uses: google-github-actions/setup-gcloud@v2
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}