ci: conditionally test turbo mode and cloud.common (#1109)

The cloud.common collection is incompatible with ansible-core >= 2.19.0.
With the current testing matrix using Python 3.12 and the ansible
milestone (currently 2.22), this incompatibility causes integration
tests to fail.

Instead of completely removing turbo mode from the testing matrix, this
commit adds ansible-core 2.18 to the matrix and excludes the combination
of the ansible milestone and turbo mode. The checkout and installation
of the cloud.common collection are now conditionally executed only when
turbo mode is enabled.

.github/workflows/integration-tests.yaml

@@ -55,13 +55,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ansible-version:
-          - milestone
+        ansible-version: ["2.18", "milestone"]
+        enable-turbo-mode: [true, false]
+        exclude:
+          - ansible-version: "milestone"
+            enable-turbo-mode: true
         python-version:
           - "3.12"
-        enable-turbo-mode:
-          - true
-          - false
         workflow-id: ${{ fromJson(needs.splitter.outputs.test_jobs) }}
     name: "integration-py${{ matrix.python-version }}-${{ matrix.ansible-version }}-${{ matrix.workflow-id }}-enable_turbo=${{ matrix.enable-turbo-mode }}"
     steps:
@@ -107,6 +107,7 @@ jobs:
           source_path: ${{ env.source }}
 
       - name: checkout ansible-collections/cloud.common
+        if: ${{ matrix.enable-turbo-mode == true }}
         uses: ansible-network/github_actions/.github/actions/checkout_dependency@main
         with:
           repository: ansible-collections/cloud.common
@@ -128,6 +129,7 @@ jobs:
           ref: main
 
       - name: install cloud.common collection
+        if: ${{ matrix.enable-turbo-mode == true }}
         uses: ansible-network/github_actions/.github/actions/build_install_collection@main
         with:
           install_python_dependencies: true