build(deps): bump github.com/open-policy-agent/opa from 1.5.0 to 1.5.1

Bumps [github.com/open-policy-agent/opa](https://github.com/open-policy-agent/opa) from 1.5.0 to 1.5.1.
- [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/v1.5.0...v1.5.1)

---
updated-dependencies:
- dependency-name: github.com/open-policy-agent/opa
  dependency-version: 1.5.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

vendor/github.com/open-policy-agent/opa/v1/topdown/walk.go

@@ -30,7 +30,7 @@ func walk(filter, path *ast.Array, input *ast.Term, iter func(*ast.Term) error)
 			pathCopy = ast.InternedEmptyArrayValue
 		} else {
 			// Shallow copy, as while the array is modified, the elements are not
-			pathCopy = path.Slice(0, path.Len())
+			pathCopy = copyShallow(path)
 		}
 
 		// TODO(ae): I'd *really* like these terms to be retrieved from a sync.Pool, and
@@ -48,8 +48,7 @@ func walk(filter, path *ast.Array, input *ast.Term, iter func(*ast.Term) error)
 		filter = filter.Slice(1, -1)
 		if key.IsGround() {
 			if term := input.Get(key); term != nil {
-				path = pathAppend(path, key)
-				return walk(filter, path, term, iter)
+				return walk(filter, pathAppend(path, key), term, iter)
 			}
 			return nil
 		}
@@ -149,6 +148,16 @@ func pathIsWildcard(operands []*ast.Term) bool {
 	return false
 }
 
+func copyShallow(arr *ast.Array) *ast.Array {
+	cpy := make([]*ast.Term, 0, arr.Len())
+
+	arr.Foreach(func(elem *ast.Term) {
+		cpy = append(cpy, elem)
+	})
+
+	return ast.NewArray(cpy...)
+}
+
 func init() {
 	RegisterBuiltinFunc(ast.WalkBuiltin.Name, evalWalk)
 }

vendor/github.com/open-policy-agent/opa/v1/version/version.go

@@ -10,7 +10,7 @@ import (
 	"runtime/debug"
 )
 
-var Version = "1.5.0"
+var Version = "1.5.1"
 
 // GoVersion is the version of Go this was built with
 var GoVersion = runtime.Version()