Pin dependencies

Author: renovate[bot]

.github/workflows/release-tags.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
         with:
           fetch-depth: 0
 

.github/workflows/validate-release-pr.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
         with:
           fetch-depth: 0
 
@@ -36,7 +36,7 @@ jobs:
       # rebuild toolchain to match promptfoo's release job (.nvmrc -> Node 24).
       - name: Set up Node.js
         if: ${{ startsWith(github.head_ref, 'release/code-scan-action-v') }}
-        uses: actions/setup-node@v6
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6
         with:
           node-version: '24'