update http links, where possible, to https

cattaz.io, unfortunately, is still only available over http, but I've raised an issue in the repo to enable https on github pages, which the site appears to be using.

README.md

@@ -48,12 +48,12 @@ Sponsorship also comes with special perks! [![Become a Sponsor](https://img.shie
 
 ## Who is using Yjs
 
-* [Relm](http://www.relm.us/) A collaborative gameworld for teamwork and
+* [Relm](https://www.relm.us/) A collaborative gameworld for teamwork and
   community. :star2:
 * [Input](https://input.com/) A collaborative note taking app. :star2:
 * [Room.sh](https://room.sh/) A meeting application with integrated
   collaborative drawing, editing, and coding tools. :star:
-* [http://coronavirustechhandbook.com/](https://coronavirustechhandbook.com/)
+* [https://coronavirustechhandbook.com/](https://coronavirustechhandbook.com/)
   A collaborative wiki that is edited by thousands of different people to work
   on a rapid and sophisticated response to the coronavirus outbreak and
   subsequent impacts. :star:
@@ -90,10 +90,10 @@ are implemented in separate modules.
 
 | Name | Cursors | Binding |  Demo |
 |---|:-:|---|---|
-| [ProseMirror](https://prosemirror.net/)                                                   | ✔ | [y-prosemirror](http://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
-| [Quill](https://quilljs.com/) | ✔ | [y-quill](http://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
-| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
-| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
+| [ProseMirror](https://prosemirror.net/)                                                   | ✔ | [y-prosemirror](https://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
+| [Quill](https://quilljs.com/) | ✔ | [y-quill](https://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
+| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](https://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
+| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](https://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
 
 ### Providers
 
@@ -103,7 +103,7 @@ manage all that for you and are the perfect starting point for your
 collaborative app.
 
 <dl>
-  <dt><a href="http://github.com/yjs/y-webrtc">y-webrtc</a></dt>
+  <dt><a href="https://github.com/yjs/y-webrtc">y-webrtc</a></dt>
   <dd>
 Propagates document updates peer-to-peer using WebRTC. The peers exchange
 signaling data over signaling servers. Publically available signaling servers
@@ -111,19 +111,19 @@ are available. Communication over the signaling servers can be encrypted by
 providing a shared secret, keeping the connection information and the shared
 document private.
   </dd>
-  <dt><a href="http://github.com/yjs/y-websocket">y-websocket</a></dt>
+  <dt><a href="https://github.com/yjs/y-websocket">y-websocket</a></dt>
   <dd>
 A module that contains a simple websocket backend and a websocket client that
 connects to that backend. The backend can be extended to persist updates in a
 leveldb database.
   </dd>
-  <dt><a href="http://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
+  <dt><a href="https://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
   <dd>
 Efficiently persists document updates to the browsers indexeddb database.
 The document is immediately available and only diffs need to be synced through the
 network provider.
   </dd>
-  <dt><a href="http://github.com/yjs/y-dat">y-dat</a></dt>
+  <dt><a href="https://github.com/yjs/y-dat">y-dat</a></dt>
   <dd>
 [WIP] Write document updates effinciently to the dat network using
 <a href="https://github.com/kappa-db/multifeed">multifeed</a>. Each client has