Update changelog for 1.20.1 patch release (#4953)

* Update changelog for 1.20.1 patch release

* Disable jApiCmp diff check on release branches

* Disable japicmp when base_ref is release

Author: jack-berg

.github/workflows/build.yml

@@ -60,6 +60,8 @@ jobs:
             -Porg.gradle.java.installations.paths=${{ steps.setup-java-test.outputs.path }},${{ steps.setup-java.outputs.path }}
 
       - name: Check for diff
+        # The jApiCmp diff compares current to latest, which isn't appropriate for release branches
+        if: ${{ !startsWith(github.ref_name, 'release/') && !startsWith(github.base_ref, 'release/') }}
         run: |
           if git diff --quiet
           then 

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+### Bugfixes
+
+* Fix bug in `ComponentRegistry` that produces `ConcurrentModificationException` when reading
+  metrics at the same time as obtaining a meter.
+  [(#4951)](https://github.com/open-telemetry/opentelemetry-java/pull/4951)
+
 ## Version 1.20.0 (2022-11-11)
 
 ### API