fix: don't try to parse response on curl nonzero exit (#238)

Author: jameshiew

lua/plenary/curl.lua

@@ -244,6 +244,15 @@ request = function(specs)
     command = "curl",
     args = args,
     on_exit = function(j, code)
+      if code ~= 0 then
+        error(string.format(
+          "%s %s - curl error exit_code=%s stderr=%s",
+          opts.method,
+          opts.url,
+          code,
+          vim.inspect(j:stderr_result())
+        ))
+      end
       local output = parse.response(j:result(), opts.dump[2], code)
       if opts.callback then
         return opts.callback(output)