remove branch from windows-function (#1151)

scripts/g.extension/g.extension.py

@@ -1231,8 +1231,7 @@ def install_extension_win(name):
     os.chdir(TMPDIR)  # this is just to not leave something behind
     srcdir = os.path.join(TMPDIR, name)
     download_source_code(source=source, url=url, name=name,
-                         outdev=outdev, directory=srcdir, tmpdir=TMPDIR,
-                         branch=branch)
+                         outdev=outdev, directory=srcdir, tmpdir=TMPDIR)
 
     # collect module names and file names
     module_list = list()