Update the CHANGELOG.md for a 85.3 release (#8127)

- Thanks for your contribution! Please replace this text with a
description of what this PR is changing or adding and why, list any
relevant issues, and review the contribution guidelines below.

---

- [ X ] I’ve reviewed the contributor guide and applied the relevant
portions to this PR.

Author: jwren

CHANGELOG.md

@@ -1,3 +1,8 @@
+# 85.3
+- Add Property Editor side panel (#7957)
+- Support removed for IDEA 2024.1 (Koala) and 2024.2 (Ladybug) (#8073)
+- Various cleanups including migrating slow operations to non-blocking calls (#8089)
+
 # 85.2
 - Fix broken devtools inspector source navigation (#8041)
 

resources/META-INF/plugin.xml

@@ -50,6 +50,12 @@
 
   <change-notes>
     <![CDATA[
+<h1>85.3</h1>
+<ul>
+  <li>Add Property Editor side panel (#7957)</li>
+  <li>Support removed for IDEA 2024.1 (Koala) and 2024.2 (Ladybug) (#8073)</li>
+  <li>Various cleanups including migrating slow operations to non-blocking calls (#8089)</li>
+</ul>
 <h1>85.2</h1>
 <ul>
   <li>Fix broken devtools inspector source navigation (#8041)</li>