chore(deps): update actions/setup-python action to v6 (#6676)

Author: renovate-bot

.github/workflows/codegen.yml

@@ -50,7 +50,7 @@ jobs:
           repository: googleapis/discovery-artifact-manager
           fetch-depth: 1
           path: discovery-artifact-manager
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.13"
       - id: find-preferred-versions
@@ -93,7 +93,7 @@ jobs:
           repository: googleapis/discovery-artifact-manager
           fetch-depth: 1
           path: discovery-artifact-manager
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.13"
       - id: find-preferred-versions

.github/workflows/tests.yml

@@ -36,7 +36,7 @@ jobs:
         steps:
             - uses: actions/checkout@v4
             - name: Set up Python
-              uses: actions/setup-python@v5
+              uses: actions/setup-python@v6
               with:
                 python-version: "3.13"
             - name: Install dependencies