Updated CHANGELOG for next release (#1146)

* Updated CHANGELOG to release for ROCm 6.1.0 (#1142)

* Fixed missing CHANGELOG notes from ROCm 5.5 through unreleased 6.1 (#1141)

* Update CHANGELOG.md for ROCm release 5.5

(cherry picked from commit 975327be45f2313dc7249f9c54ad90870e833a4a)

* Update CHANGELOG.md for ROCm 5.7.0

(cherry picked from commit ac8db8d8e0853f1783c10e2858f6c3b86e4d27cb)

* Added ROCm 6.0 and 6.1 CHANGELOG notes.

---------

Co-authored-by: gilbertlee-amd <44450918+gilbertlee-amd@users.noreply.github.com>
(cherry picked from commit 3361abe786)

* Updated CHANGELOG to release for ROCm 6.1.0

* Removed empty sections from CHANGELOG in latest releases.

(cherry picked from commit 164c9553717f2c3bce86a372764ea73030dd5f72)

* Reverted ROCm 6.1.0 block to "Unreleased"

CHANGELOG.md

@@ -2,33 +2,7 @@
 
 Full documentation for RCCL is available at [https://rccl.readthedocs.io](https://rccl.readthedocs.io)
 
-## Unreleased - RCCL 2.18.6 for ROCm 6.1.0
-### Changed
-- Compatibility with NCCL 2.18.6
-### Added
-### Fixed
-### Removed
-
-## RCCL 2.18.3 for ROCm 6.0.0
-### Changed
-- Compatibility with NCCL 2.18.3
-### Added
-### Fixed
-### Removed
-
-## RCCL 2.17.1-1 for ROCm 5.7.0
-### Changed
-- Compatibility with NCCL 2.17.1-1
-- Performance tuning for some collective operations
-### Added
-- Minor improvements to MSCCL codepath
-- NCCL_NCHANNELS_PER_PEER support
-- Improved compilation performance
-- Support for gfx94x
-### Fixed
-- Potential race-condition during ncclSocketClose()
-
-## RCCL 2.16.2 for ROCm 5.6.0
+## Unreleased
 ### Changed
 - Modifying rings to be rail-optimized topology friendly
 ### Added
@@ -38,16 +12,10 @@ Full documentation for RCCL is available at [https://rccl.readthedocs.io](https:
 ## Unreleased - RCCL 2.18.6 for ROCm 6.1.0
 ### Changed
 - Compatibility with NCCL 2.18.6
-### Added
-### Fixed
-### Removed
 
 ## RCCL 2.18.3 for ROCm 6.0.0
 ### Changed
 - Compatibility with NCCL 2.18.3
-### Added
-### Fixed
-### Removed
 
 ## RCCL 2.17.1-1 for ROCm 5.7.0
 ### Changed
@@ -64,10 +32,8 @@ Full documentation for RCCL is available at [https://rccl.readthedocs.io](https:
 ## RCCL 2.16.2 for ROCm 5.6.0
 ### Changed
 - Compatibility with NCCL 2.16.2
-### Added
 ### Fixed
 - Remove workaround and use indirect function call
-### Removed
 
 ## RCCL 2.15.5 for ROCm 5.5.0
 ### Changed