[infra] Upgrade Go to 1.11

Bug: skia:
Change-Id: I7fc9b7a208c8edf5be970f5139e1916a756288af
Reviewed-on: https://skia-review.googlesource.com/156680
Commit-Queue: Stephan Altmueller <stephana@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
3 files changed