[FIX] google_drive: Use 'get' instead of 'post' in 'copy_doc'

Purpose
=======

This chunk of code was badly converted in P3 on https://github.com/odoo/odoo/commit/01e35141479b8dfc4a390518f89fc52e7cec5396#diff-6ad3d62d2147f2fef519473f2576b459R94

addons/google_drive/models/google_drive.py

@@ -91,7 +91,7 @@ class GoogleDrive(models.Model):
         request_url = "https://www.googleapis.com/drive/v2/files/%s?fields=parents/id&access_token=%s" % (template_id, access_token)
         headers = {"Content-type": "application/x-www-form-urlencoded"}
         try:
-            req = requests.post(request_url, headers=headers, timeout=TIMEOUT)
+            req = requests.get(request_url, headers=headers, timeout=TIMEOUT)
             req.raise_for_status()
             parents_dict = req.json()
         except requests.HTTPError: