Update CHANGELOG.md

Fixing the headers. levels  This messed up the doc changelog collection script and missed rocBLAS changelogs.  Luckily, we caught it with manual inspection.

Author: yhuiYH

CHANGELOG.md

@@ -5,17 +5,17 @@ Documentation for rocBLAS is available at
 
 ## rocBLAS 4.1.0 for ROCm 6.1
 
-## Additions
+### Additions
 
 * Level 1 and Level 1 Extension functions have additional ILP64 API for both C and FORTRAN (_64 name suffix) with int64_t function arguments.
 * Cache flush timing for gemm_ex.
 
-## Changes
+### Changes
 
 * Some Level 2 function argument names have changed 'm' to 'n' to match legacy BLAS, there was no change in implementation.
 * Standardized the use of non-blocking streams for copying results from device to host.
 
-## Fixes
+### Fixes
 
 * Fixed host-pointer mode reductions for non-blocking streams.