Adding release notes for 2.3.0 (#2430)
Adding release notes for 2.3.0 (#2430)

* Adding release notes for 2.3.0

* Update releasenotes.md

ROCmSoftwarePlatform/MIOpen,ROCmSoftwarePlatform/MIOpen,ROCmSoftwarePlatform/MIOpen,ROCmSoftwarePlatform/MIOpen,ROCmSoftwarePlatform/MIOpen