Update luci-go client

This is mainly to pick up below change.
https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/1105680

Change-Id: I1369f416e81cd8582dfd847589b1996bb38e6064
Reviewed-on: https://chromium-review.googlesource.com/1154864Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579300}

DEPS

@@ -339,7 +339,7 @@ deps = {
       'packages': [
         {
           'package': 'infra/tools/luci/isolate/${{platform}}',
-          'version': 'git_revision:8b15ba47cbaf07a56f93326e39f0c8e5069c19e8',
+          'version': 'git_revision:bc125484b8513898f17bc2501ac5e95330f44a3b',
         },
       ],
       'dep_type': 'cipd',