Update cache action version from v2 to v4 (#2105)

Author: jonathanmetzman

.github/workflows/presubmit.yml

@@ -27,7 +27,7 @@ jobs:
     # Copied from:
     # https://docs.github.com/en/actions/language-and-framework-guides/using-python-with-github-actions
     - name: Cache pip
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         # This path is specific to Ubuntu.
         path: ~/.cache/pip