Using bazelisk on macOS CI (#1049)

.circleci/config.yml

diff --git a/.circleci/config.yml b/.circleci/config.yml
index e21abe9..71292f7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -201,9 +201,9 @@
       - checkout
       - run: brew install grep
       - run:
-          name: install bazel
+          name: install bazelisk
           command: |
-            brew install bazel
+            brew install bazelisk
       - run: test/test_bazel_mac.sh
 
   test-bazel-windows: