idf_tools.py: avoid splittype call deprecated in python3.8

Closes https://github.com/espressif/esp-idf/issues/6200

tools/idf_tools.py

@@ -64,11 +64,10 @@ except ImportError:
     pass
 
 try:
-    from urllib.parse import splittype
     from urllib.request import urlopen
     from urllib.error import ContentTooShortError
 except ImportError:
-    from urllib import urlopen, splittype, ContentTooShortError
+    from urllib import urlopen, ContentTooShortError
 
 try:
     from exceptions import WindowsError
@@ -305,6 +304,14 @@ def unpack(filename, destination):
     archive_obj.extractall(destination)
 
 
+def splittype(url):
+    match = re.match('([^/:]+):(.*)', url, re.DOTALL)
+    if match:
+        scheme, data = match.groups()
+        return scheme.lower(), data
+    return None, url
+
+
 # An alternative version of urlretrieve which takes SSL context as an argument
 def urlretrieve_ctx(url, filename, reporthook=None, data=None, context=None):
     url_type, path = splittype(url)