chore: fix bazel example

[y1hao]

One bazel example was added in #798 to use as part of CI to verify bazel build keeps working. However, the example doesn't work if run with bazel run locally, because it doesn't include the example jsonnet file as data. This probably doesn't matter since the CI only cares about bazel build. However, since people may come here to get an idea of how to use bazel with jsonnet, it's probably nicer just to make the bazel run command able to run as well.