Update go.skia.org/infra in go.mod/go.sum

To pick up https://skia.googlesource.com/buildbot/+/e9c390189fa6ab596ffe4575b46f8f7a0cf1b59e

Updated with:
$ go get go.skia.org/infra@e9c390189fa6ab596ffe4575b46f8f7a0cf1b59e
$ make -C infra/bots train

Bug: skia:11034
Change-Id: Ic34a8007563953afd02ad51bcacb972e5bdf0973
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/344971
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
diff --git a/go.sum b/go.sum
index 8dcefc7..b80955e 100644
--- a/go.sum
+++ b/go.sum
@@ -1546,6 +1546,8 @@
 go.skia.org/infra v0.0.0-20201211124251-12d4265d9508/go.mod h1:7t8Lju542R6/LHj4Swn4cGWHPYylIAQPGeS5V0fpFPU=
 go.skia.org/infra v0.0.0-20201217154708-25854a97e536 h1:jOJz5EMh0nf54wV8CQpTyuPx7N2kz3cGkYim8prurPc=
 go.skia.org/infra v0.0.0-20201217154708-25854a97e536/go.mod h1:5q1SY6pVIsvuPD68rYiVzgjguBKFy1DlJN5UzFem3uk=
+go.skia.org/infra v0.0.0-20201221193112-e9c390189fa6 h1:Si4o3D+S8uveMzJlwP6Xpuo8hwwDMIJl/6w0Ub+6d8I=
+go.skia.org/infra v0.0.0-20201221193112-e9c390189fa6/go.mod h1:5q1SY6pVIsvuPD68rYiVzgjguBKFy1DlJN5UzFem3uk=
 go.starlark.net v0.0.0-20201118183435-e55f603d8c79/go.mod h1:5YFcFnRptTN+41758c2bMPiqpGg4zBfYji1IQz8wNFk=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=