Update put.js send 200 or 201 depending on prexistance of resource

The HTTP spec says that the Server MUST return a 200 or 204 if PUT replaces and existing resource.  See second paragraph of https://httpwg.org/specs/rfc9110#PUT.

Brought up by @CxRes.

lib/handlers/put.js

@@ -62,6 +62,7 @@ async function putStream (req, res, next, stream = req) {
   // try {
   // Obtain details of the target resource
   let resourceExists = true
+  let returnStatus = 201;
   try {
     // First check if the file already exists
     await ldp.resourceMapper.mapUrlToFile({ url: req })
@@ -70,14 +71,15 @@ async function putStream (req, res, next, stream = req) {
       res.sendStatus(412)
       return next()
     }
+    returnStatus = 200;
   } catch (err) {
     resourceExists = false
   }
   try {
     // Fails with Append on existing resource
     if (!req.originalUrl.endsWith('.acl')) await checkPermission(req, resourceExists)
     await ldp.put(req, stream, getContentType(req.headers))
-    res.sendStatus(201)
+    res.sendStatus(returnStatus)
     return next()
   } catch (err) {
     err.message = 'Can\'t write file/folder: ' + err.message