ci: adjust bazel cache dir

.github/workflows/verible-ci.yml

diff --git a/.github/workflows/verible-ci.yml b/.github/workflows/verible-ci.yml
index bc3fc34..eef6fb2 100644
--- a/.github/workflows/verible-ci.yml
+++ b/.github/workflows/verible-ci.yml
@@ -79,7 +79,7 @@
       with:
         path: |
           /tmp/clang-tidy-hashes.cache
-          /home/runner/.cache/bazel
+          /root/.cache/bazel
         key: clang-tidy-${{ steps.cache_timestamp.outputs.time }}
         restore-keys: clang-tidy-
 
@@ -129,7 +129,7 @@
       uses: actions/cache@v2
       if: matrix.mode != 'clean' && matrix.mode != 'coverage'
       with:
-        path: "/home/runner/.cache/bazel"
+        path: "/root/.cache/bazel"
         key: bazelcache_${{ matrix.mode }}_${{ steps.cache_timestamp.outputs.time }}
         restore-keys: bazelcache_${{ matrix.mode }}_