Release version 0.8.1

[hannobraun]

I'd like to get a new release out quickly, to test #277 and hopefully get documentation fixed.

The following still needs to be done:

• @david-sawatzke:
  • Review/merge Attempt to fix docs.rs build #277
  • Review/approve this pull request
• @hannobraun:
  • Rebase after Attempt to fix docs.rs build #277 has been merged
  • Update date in changelog, as required
  • Publish on crates.io
  • Merge this pull request
  • Create and push release tag

[hannobraun]

All done! Let's see how it turns out.

[hannobraun]

It worked: https://docs.rs/lpc8xx-hal/0.8.1/lpc8xx_hal/