Use any in place of interface{} (#7566)

Earlier this evening I tried to run the Go
[modernize](https://pkg.go.dev/golang.org/x/tools/gopls/internal/analysis/modernize)
analyzer on OPA. That didn't go as planned:

- https://github.com/golang/go/issues/73661
- https://github.com/golang/go/issues/73663

While we wait for that to be fixed, I figured an old-fashioned
search-and-replace across the repo may work for at least the
`interface{}` to `any` conversion. That should help make it easier
to see the other fixes as applied by the modernize tool once it has
had those issues resolved.

Signed-off-by: Anders Eknert <anders@styra.com>

server/authorizer/authorizer.go

@@ -60,12 +60,12 @@ func NewBasic(inner http.Handler, compiler func() *ast.Compiler, store storage.S
 
 // SetBodyOnContext adds the parsed input value to the context. This function is only
 // exposed for test purposes.
-func SetBodyOnContext(ctx context.Context, x interface{}) context.Context {
+func SetBodyOnContext(ctx context.Context, x any) context.Context {
 	return v1.SetBodyOnContext(ctx, x)
 }
 
 // GetBodyOnContext returns the parsed input from the request context if it exists.
 // The authorizer saves the parsed input on the context when it runs.
-func GetBodyOnContext(ctx context.Context) (interface{}, bool) {
+func GetBodyOnContext(ctx context.Context) (any, bool) {
 	return v1.GetBodyOnContext(ctx)
 }

server/types/types.go

@@ -27,7 +27,7 @@ const (
 type ErrorV1 = v1.ErrorV1
 
 // NewErrorV1 returns a new ErrorV1 object.
-func NewErrorV1(code, f string, a ...interface{}) *ErrorV1 {
+func NewErrorV1(code, f string, a ...any) *ErrorV1 {
 	return v1.NewErrorV1(code, f, a...)
 }
 

server/writer/writer.go

@@ -40,12 +40,12 @@ func Error(w http.ResponseWriter, status int, err *types.ErrorV1) {
 // Deprecated: This method is problematic when using a non-200 status `code`: if
 // encoding the payload fails, it'll print "superfluous call to WriteHeader()"
 // logs.
-func JSON(w http.ResponseWriter, code int, v interface{}, pretty bool) {
+func JSON(w http.ResponseWriter, code int, v any, pretty bool) {
 	v1.JSON(w, code, v, pretty)
 }
 
 // JSONOK is a helper for status "200 OK" responses
-func JSONOK(w http.ResponseWriter, v interface{}, pretty bool) {
+func JSONOK(w http.ResponseWriter, v any, pretty bool) {
 	v1.JSONOK(w, v, pretty)
 }