Fix for Bazel upcoming change incompatible_string_join_requires_strings (#135)
Fix for Bazel upcoming change incompatible_string_join_requires_strings (#135)

The argument of string.join should be a list of strings. In the future,
Bazel won't perform this implicit conversion.
bazelbuild/bazel-integration-testing,bazelbuild/bazel-integration-testing,bazelbuild/bazel-integration-testing