update RELEASE_NOTES.md

Author: stefanmaierhofer

.github/workflows/publish.yml

@@ -3,6 +3,7 @@ on:
   push:
     branches:
       - master
+      - 5.1-maintenance
       - newbuild
     paths:
       - RELEASE_NOTES.md

RELEASE_NOTES.md

@@ -1,6 +1,8 @@
 ### 5.1.35
 - merged `5.1.30.1` and `5.1.30.2`
 - cherry picked all commits from `master` branch, which are not related to 5.2.x upgrade
+- add branch `5.1-maintenance` to `.github/workflows/publish.yml`
+- fix warning (deprecated `WebClient`)
 
 ### 5.1.34
 - [IPointCloudNode] FilterConvexHulls3d: polygon is CCW