chore: add /v2 to import module path (#9072)

* chore: add /v2 to import module path

go mod requires semantic versioning with versions greater than 1.x

This was a mechanical update by running:
```
go install github.com/marwan-at-work/mod/cmd/mod@latest
mod upgrade
```

Migrate generated files to import /v2

* Fix gen

examples/examples.go

@@ -14,7 +14,7 @@ import (
 	"golang.org/x/sync/singleflight"
 	"golang.org/x/xerrors"
 
-	"github.com/coder/coder/codersdk"
+	"github.com/coder/coder/v2/codersdk"
 )
 
 var (

examples/examples_test.go

@@ -10,7 +10,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/coder/coder/examples"
+	"github.com/coder/coder/v2/examples"
 )
 
 func TestTemplate(t *testing.T) {