SBI v0.3.0 released


We have released SBI specification v0.3.0[1]. It's been month since the
release candidate (v.0.3-rc1). There were only includes few typo fixes
and license update patches after that. That's why, we think the current
version is good enough to be tagged as a official release.

To summarize v0.3.0 includes few new extensions and cosmetic changes
through out the entire specification.

Here are few notable changes:

- New extensions:
- SBI PMU extension
- SBI System reset extension
- Updated extensions:
- Hart Suspend function added to HSM extension
- Overall specification reorganization and style update

Thank you for your contributions!