Merge pull request #51375 from cblecker/go1.9

Automatic merge from submit-queue (batch tested with PRs 54045, 51375). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Upgrade to go1.9

**What this PR does / why we need it**:
Upgrade to go1.9. Upgrading is good. It's "the best golang release ever"!

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #49484

**Special notes for your reviewer**:

**Release note**:

```release-note
Upgrade to go1.9
```

/assign @luxas @ixdy @wojtek-t

build/build-image/cross/Dockerfile

@@ -15,7 +15,7 @@
 # This file creates a standard build environment for building cross
 # platform go binary for the architecture kubernetes cares about.
 
-FROM golang:1.8.3
+FROM golang:1.9.1
 
 ENV GOARM 7
 ENV KUBE_DYNAMIC_CROSSPLATFORMS \

build/build-image/cross/VERSION

@@ -1 +1 @@
-v1.8.3-3
+v1.9.1-1

build/root/WORKSPACE

@@ -1,8 +1,8 @@
 http_archive(
     name = "io_bazel_rules_go",
-    sha256 = "a4ea00b71a6fc3bd381cbbf6eb83ec91fe8b32b1c622c048f1e6f0d965bb1a2d",
-    strip_prefix = "rules_go-a280fbac1a0a4c67b0eee660b4fd1b3db7c9f058",
-    urls = ["https://github.com/bazelbuild/rules_go/archive/a280fbac1a0a4c67b0eee660b4fd1b3db7c9f058.tar.gz"],
+    sha256 = "441e560e947d8011f064bd7348d86940d6b6131ae7d7c4425a538e8d9f884274",
+    strip_prefix = "rules_go-c72631a220406c4fae276861ee286aaec82c5af2",
+    urls = ["https://github.com/bazelbuild/rules_go/archive/c72631a220406c4fae276861ee286aaec82c5af2.tar.gz"],
 )
 
 http_archive(
@@ -49,7 +49,7 @@ load("@io_bazel_rules_docker//docker:docker.bzl", "docker_repositories", "docker
 go_rules_dependencies()
 
 go_register_toolchains(
-    go_version = "1.8.3",
+    go_version = "1.9.1",
 )
 
 docker_repositories()