build(deps): bump github.com/open-policy-agent/opa from 0.51.0 to 0.59.0

Bumps [github.com/open-policy-agent/opa](https://github.com/open-policy-agent/opa) from 0.51.0 to 0.59.0.
- [Release notes](https://github.com/open-policy-agent/opa/releases)
- [Changelog](https://github.com/open-policy-agent/opa/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-policy-agent/opa/compare/v0.51.0...v0.59.0)

---
updated-dependencies:
- dependency-name: github.com/open-policy-agent/opa
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/open-policy-agent/opa/util/json.go

@@ -11,7 +11,9 @@ import (
 	"io"
 	"reflect"
 
-	"github.com/ghodss/yaml"
+	"sigs.k8s.io/yaml"
+
+	"github.com/open-policy-agent/opa/loader/extension"
 )
 
 // UnmarshalJSON parses the JSON encoded data and stores the result in the value
@@ -19,10 +21,17 @@ import (
 //
 // This function is intended to be used in place of the standard json.Marshal
 // function when json.Number is required.
-func UnmarshalJSON(bs []byte, x interface{}) (err error) {
+func UnmarshalJSON(bs []byte, x interface{}) error {
+	return unmarshalJSON(bs, x, true)
+}
+
+func unmarshalJSON(bs []byte, x interface{}, ext bool) error {
 	buf := bytes.NewBuffer(bs)
 	decoder := NewJSONDecoder(buf)
 	if err := decoder.Decode(x); err != nil {
+		if handler := extension.FindExtension(".json"); handler != nil && ext {
+			return handler(bs, x)
+		}
 		return err
 	}
 
@@ -103,14 +112,18 @@ func Reference(x interface{}) *interface{} {
 	return &x
 }
 
-// Unmarshal decodes a YAML or JSON value into the specified type.
+// Unmarshal decodes a YAML, JSON or JSON extension value into the specified type.
 func Unmarshal(bs []byte, v interface{}) error {
 	if json.Valid(bs) {
-		return UnmarshalJSON(bs, v)
+		return unmarshalJSON(bs, v, false)
 	}
-	bs, err := yaml.YAMLToJSON(bs)
-	if err != nil {
-		return err
+	nbs, err := yaml.YAMLToJSON(bs)
+	if err == nil {
+		return unmarshalJSON(nbs, v, false)
 	}
-	return UnmarshalJSON(bs, v)
+	// not json or yaml: try extensions
+	if handler := extension.FindExtension(".json"); handler != nil {
+		return handler(bs, v)
+	}
+	return err
 }