[StepSecurity] ci: Harden GitHub Actions

Signed-off-by: StepSecurity Bot <bot@stepsecurity.io>

.github/workflows/api-release.yml

@@ -22,7 +22,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
         with:
           ref: ${{ github.ref }}
           path: src/github.com/containerd/containerd
@@ -50,7 +50,7 @@ jobs:
         working-directory: src/github.com/containerd/containerd
 
       - name: Save release notes
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
         with:
           name: containerd-release-notes
           path: src/github.com/containerd/containerd/release-notes.md
@@ -65,11 +65,11 @@ jobs:
     needs: [check]
     steps:
       - name: Download release notes
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
         with:
           path: builds
       - name: Create Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@c062e08bd532815e2082a85e87e3ef29c3e6d191 # v2.0.8
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           fail_on_unmatched_files: true