docs: explain that dual import is not recommended

Signed-off-by: Charlie Egan <charlie@styra.com>

docs/content/v0-compatibility.md

@@ -114,10 +114,8 @@ r := rego.New(
 )
 ```
 
-Finally, another option is to import the `v0` package instead. This can even be
-used alongside the `v1` package in the same program if required. The program
-below will evaluate the same Rego using both the v0 and v1 Rego packages, v1 is
-running in v0 compatibility mode with `SetRegoVersion`:
+Finally, another option is to import the `v0` package instead. The program
+below imports the v0 package instead:
 
 ```go
 package main
@@ -128,30 +126,17 @@ import (
 	"fmt"
 
 	v0rego "github.com/open-policy-agent/opa/rego"
-	v1ast "github.com/open-policy-agent/opa/v1/ast"
-	v1rego "github.com/open-policy-agent/opa/v1/rego"
+	// v1rego "github.com/open-policy-agent/opa/v1/rego"
 )
 
 func main() {
-	// we have a v0 Rego module, we want to evaluate it using the v1 rego
-	// package and the v0 rego package in the same program.
 	module := `package example
 
 messages[msg] {
 	msg := "foo"
 }
 `
 
-	rv1 := v1rego.New(
-		v1rego.Query("data.example.messages"),
-		v1rego.SetRegoVersion(v1ast.RegoV0),
-		v1rego.Module("example.rego", module),
-	)
-
-	rs, _ := rv1.Eval(context.TODO())
-	bs, _ := json.Marshal(rs)
-	fmt.Println(string(bs))
-
 	rv0 := v0rego.New(
 		v0rego.Query("data.example.messages"),
 		v0rego.Module("example.rego", module),
@@ -164,6 +149,11 @@ messages[msg] {
 }
 ```
 
+{{< danger >}}
+**Note**: Using v0 packages and v1 packages in the same program is not
+recommended. Interoperability between the two packages is not guaranteed.
+{{< /danger >}}
+
 ### v0.x compatibility mode in the OPA Go SDK
 
 {{< info >}}