Merge bitcoin-core#1486: ci: Update cache action

94a14d5 ci: Update cache action (Hennadii Stepanov)

Pull request description:

  This PR fixes deprecation warnings for Node.js 16 actions in the GHA CI.

  See:
  - https://github.com/marketplace/actions/cache
  - https://github.com/actions/cache/releases/tag/v4.0.0

ACKs for top commit:
  real-or-random:
    ACK 94a14d5 thanks!

Tree-SHA512: 6f520908aaadf179955255a2b3a93c2cb96f23cf3a9d00a53b3ae635007983337f1a768cb6039e0e0b1bc9630930b143dd1c650f366185fd20727ab97221519b

.github/actions/install-homebrew-valgrind/action.yml

@@ -16,7 +16,7 @@ runs:
         cat valgrind_fingerprint
       shell: bash
 
-    - uses: actions/cache@v3
+    - uses: actions/cache@v4
       id: cache
       with:
         path: ${{ env.CI_HOMEBREW_CELLAR_VALGRIND }}