Bump golang to 1.18.1

Also update all use of 'go get' => 'go install', update CI tooling for
1.18 compatibility, and gofmt everything so lint passes.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>

pkg/cli/cmds/const_windows.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package cmds

pkg/cli/cmds/init_default.go

@@ -1,3 +1,4 @@
+//go:build !linux || !cgo
 // +build !linux !cgo
 
 package cmds

pkg/cli/cmds/log_default.go

@@ -1,3 +1,4 @@
+//go:build !linux || !cgo
 // +build !linux !cgo
 
 package cmds

pkg/cli/cmds/nostage.go

@@ -1,3 +1,4 @@
+//go:build no_stage
 // +build no_stage
 
 package cmds