chore: bump to GHA actions/cache@v4 (#94)

Author: gregmagolan

.github/workflows/ci.yaml

@@ -79,7 +79,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Mount bazel caches
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             ~/.cache/bazel-disk-cache

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Mount bazel caches
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             "~/.cache/bazel"