Build broken with Bazel at HEAD

[laszlocsomor]

Describe the bug

Build is broken on Bazel CI with Bazel at HEAD (bazelbuild/bazel@f5b9d93).

Log: https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/1360#b9e885da-048d-417f-b20f-7913c7567a8a

Other projects also broke with the same culprit: Maven no longer supports fetching from "http" URLs. Those projects just needed to upgrade their external repo dependencies, e.g. like so: bazelbuild/codelabs#30

To Reproduce

Not sure. I couldn't set up the build locally.

Expected behavior
A clear and concise description of what you expected to happen.

Environment

• OS name + version: Linux
• Bazel version: HEAD (bazelbuild/bazel@f5b9d93)
• Version of the rules: 2f7e890

Additional context

Possibly related: #1217

[aherrmann]

https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/1360#b9e885da-048d-417f-b20f-7913c7567a8a/628-649

ERROR: An error occurred during the fetch of repository 'org_apache_spark_spark_core_2_10':
  | java.io.IOException: Error downloading [http://central.maven.org/maven2/org/apache/spark/spark-core_2.10/1.6.0/spark-core_2.10-1.6.0.jar] to /var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/b2c74d366118053922794e90182145d4/external/org_apache_spark_spark_core_2_10/spark-core_2.10-1.6.0.jar: GET returned 501 HTTPS Required

This has been fixed by #1214 (which was merged after 2f7e890)

[laszlocsomor]

Cool, thanks for the quick response!