ci: bump cache action to v3

.github/workflows/verible-ci.yml

diff --git a/.github/workflows/verible-ci.yml b/.github/workflows/verible-ci.yml
index 7fcd9f3..86c505e 100644
--- a/.github/workflows/verible-ci.yml
+++ b/.github/workflows/verible-ci.yml
@@ -78,7 +78,7 @@
         format: 'YYYY-MM-DD-HH-mm-ss'
 
     - name: Retrieve cached results
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
         path: |
           /tmp/clang-tidy-hashes.cache
@@ -129,7 +129,7 @@
         format: 'YYYY-MM-DD-HH-mm-ss'
 
     - name: Mount bazel cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       if: matrix.mode != 'clean' && matrix.mode != 'coverage'
       with:
         path: "/root/.cache/bazel"