logicalhan: Automated cherry pick of #75529: bump required minimum go version to 1.12.1 (strings pkg compatibility)

JobBuild
75530
03-20 23:13
98f94d83
03-20 23:12
pull-kubernetes-bazel-build 77155
pull-kubernetes-bazel-test 79949
pull-kubernetes-cross 10188
pull-kubernetes-e2e-gce 73042
pull-kubernetes-e2e-gce-device-plugin-gpu 63008
pull-kubernetes-godeps 3946
pull-kubernetes-integration 49169
pull-kubernetes-kubemark-e2e-gce-big 41841 41833
pull-kubernetes-node-e2e 123813
pull-kubernetes-typecheck 44137
pull-kubernetes-verify 126560