chore(blog): add release notes for 2.3 release

Contributes to: asyncapi/spec#675

Signed-off-by: Dale Lane <[email protected]>

pages/blog/release-notes-2.3.0.md

@@ -0,0 +1,24 @@
+---
+title: AsyncAPI Spec 2.3.0 Release Notes
+date: 2021-12-14T18:00:00+01:00
+type: Communication
+tags:
+  - specification
+  - release
+cover: /img/posts/release-notes-2.3.0/cover.webp
+authors:
+  - name: Lukasz Gornicki
+    photo: /img/avatars/lpgornicki.webp
+    link: https://twitter.com/derberq
+    byline: AsyncAPI Maintainer and Community Guardian
+excerpt: 'TODO: write excerpt'
+featured: true
+---
+
+- put good overview
+- each section should represent a feature
+  - clear info about feature
+  - use case
+  - contributor
+  - link to PR
+- last section should have additional thank you towards other people involved in the release success