Set BAZELISK_GITHUB_TOKEN.

Change-Id: Ia1beb6fde2c61aebb96de1f05089f491da09a09f
Reviewed-on: https://code-review.googlesource.com/c/re2/+/57816
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/.github/workflows/ci-bazel.yml b/.github/workflows/ci-bazel.yml
index cf4c77a..9aec657 100644
--- a/.github/workflows/ci-bazel.yml
+++ b/.github/workflows/ci-bazel.yml
@@ -9,6 +9,8 @@
       fail-fast: false
       matrix:
         os: [macos-latest, ubuntu-latest, windows-latest]
+    env:
+      BAZELISK_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
     - uses: actions/checkout@v2
     - run: .github/bazel.sh