chore: refactor workflow writting (#2225)

# What does this PR do?

Use a composite action to avoid similar steps repetitions and
centralization of the defaults.

Signed-off-by: Sébastien Han <seb@redhat.com>

.github/workflows/unit-tests.yml

@@ -30,17 +30,11 @@ jobs:
           - "3.12"
           - "3.13"
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
-      - name: Set up Python ${{ matrix.python }}
-        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ matrix.python }}
-
-      - uses: astral-sh/setup-uv@6b9c6063abd6010835644d4c2e1bef4cf5cd0fca # v6.0.1
-        with:
-          python-version: ${{ matrix.python }}
-          enable-cache: false
+      - name: Install dependencies
+        uses: ./.github/actions/setup-runner
 
       - name: Run unit tests
         run: |