adding the first draft of changelog

[illsilin]

Please feel free to add more contents as needed.

In the future, every time you make a major commit, you should add a line about it in the changelog.md file.

[geyyer]

LGTM! Let's get it started!

[aosewski]

@illsilin What do you think about adding PR# for each bullet in Changelog?

[illsilin]

I personally think adding the PR# or commit hash to the changelog would be useful. But the instruction was to create the changelog following the same format as other ROCM libraries, e.g. rocFFT:

https://github.com/ROCmSoftwarePlatform/rocFFT/blob/develop/CHANGELOG.md

I'll check with Jun or whoever is in charge of this what they think.

[illsilin]

OK, sounds like we can add the PR# or commit hash if we like.

[zjing14]

LGTM