ci(ENG-3243): move action pins off the deprecated Node 20 runtime

Swap every JavaScript action that still declares the node20 (or older)
runtime for a release that declares node24, keeping this repo's pin
style. Workflows that push take checkout v5 rather than v6, so their
credential handling is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: elgordomac

.github/workflows/release-please.yml

@@ -14,7 +14,7 @@ jobs:
       contents: write
       pull-requests: write
     steps:
-      - uses: googleapis/release-please-action@5c625bfb5d1ff62eadeeb3772007f7f66fdcf071 # v4.4.1
+      - uses: googleapis/release-please-action@45996ed1f6d02564a971a2fa1b5860e934307cf7 # v5.0.0
         with:
           config-file: .release-please-config.json
           manifest-file: .release-please-manifest.json

.github/workflows/validate.yml

@@ -16,7 +16,7 @@ jobs:
     name: Validate marketplace.json
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Validate plugin manifests
         run: npx --yes @anthropic-ai/claude-code@2.1.234 plugin validate .