v5.3.3 — the update check now works

The update check was pointed at a URL that answers every unknown path with the
site's own HTML. The updater fetched that, failed to read it as JSON, and
concluded there was nothing new — which from wp-admin is indistinguishable from
being up to date. It had never worked.

It now reads releases/latest/download/plugin.json from this repository, which
GitHub keeps pointing at the newest published release.

This one has to be installed by hand, once. The copy on your site is still
asking the old address, so it cannot fetch the release that fixes it. After
this, updates appear in wp-admin on their own.

Plugins → Add New Plugin → Upload Plugin → Replace current with uploaded.
Do not deactivate and delete — deleting runs the uninstaller.

Everything in v5.3.2 is included: six security fixes, clickjacking among them. If you are on 5.3.0 or 5.3.1, this is the one to install.

sha256  76dfa2b5cedf60db41faf7677f4f2846e1f08f26bec852e3779c3fc742f66f99