Fix downloading updates for packages with non-ASCII descriptions

* lisp/emacs-lisp/package.el (package--download-one-archive):
Make sure archive contents are written using UTF-8 encoding.
(Bug#34909)
(list-packages): Set buffer's encoding to UTF-8.
1 job for emacs-26 in 25 minutes and 11 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #1070
test

00:25:11