[buildbucket] increase the cron interval for report_builder_metrics
[buildbucket] increase the cron interval for report_builder_metrics

Currently, each run takes ~2m50s.
In PyBB, computing global metrics took ~3m50s.

Bug: 1249664
Change-Id: Id7c92bdc59dd4f031080f6dca9599b5c2f341b42
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/3315268
Auto-Submit: Scott Lee <1dcb292530f82960316cb3d87cd67c3f212b79cb@chromium.org>
Reviewed-by: smut <95deb7aa15d4c615299e47e7688551456568b1fb@google.com>
Commit-Queue: smut <95deb7aa15d4c615299e47e7688551456568b1fb@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go