Use Go 1.18 to build and test containerd

Go 1.18 is released. Go 1.16 is no longer supported by the Go team.
golangci-lint is updated since 1.44.2 doesn't support Go 1.18.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

Vagrantfile

@@ -77,7 +77,7 @@ Vagrant.configure("2") do |config|
   config.vm.provision "install-golang", type: "shell", run: "once" do |sh|
     sh.upload_path = "/tmp/vagrant-install-golang"
     sh.env = {
-        'GO_VERSION': ENV['GO_VERSION'] || "1.17.8",
+        'GO_VERSION': ENV['GO_VERSION'] || "1.18",
     }
     sh.inline = <<~SHELL
         #!/usr/bin/env bash