ci: pin checkout and Python setup actions

.gitea/workflows/ci.yml

@@ -11,8 +11,8 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with: { python-version: "3.11" }
       - run: pip install -r requirements.txt
       - run: pip install -r requirements-audit.txt
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: lint
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Build deterministic release bundle
         run: |
           SOURCE_DATE_EPOCH="$(git show -s --format=%ct "$GITHUB_SHA")"
@@ -44,8 +44,8 @@ jobs:
     env:
       STACKCHAIN_RUN_RELEASE_E2E: "1"
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
         with: { python-version: "3.11" }
       - name: Download assembled release bundle
         uses: actions/download-artifact@v3
@@ -66,7 +66,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Download tested release bundle
         uses: actions/download-artifact@v3
         with: