npm install -g is needed and it works after all

I can't reproduce the permissions failure I got before when trying to
use `-g`. Oh well.

Author: mhucka

.github/actions/set-up-bazel/action.yaml

@@ -58,7 +58,7 @@ runs:
       env:
         BAZELISK_SHOW_PROGRESS: ${{inputs.debug || runner.debug}}
       shell: bash
-      run: npm install @bazel/bazelisk
+      run: npm install -g @bazel/bazelisk
 
     # This cache stores copies of Bazel downloaded by Bazelisk. The copies are
     # stored in subdirs coded by hash numbers, and thus this cache can be