chore(deps): bump actions/cache from 3 to 4 (All-Hands-AI#5801)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/openhands-resolver.yml

@@ -100,7 +100,7 @@ jobs:
               contains(github.event.review.body, '@openhands-agent-exp')
             )
           )
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ env.pythonLocation }}/lib/python3.12/site-packages/*
           key: ${{ runner.os }}-pip-openhands-resolver-${{ hashFiles('requirements.txt') }}