This is a smaller step than !1 (closed), and probably better considering !1 (closed) relied on a rc3 release.
In this case I found a couple commits to cherry-pick from the new upstream which occurred fairly close after the 0.8.0 source. These changes made the doc8 package no longer rely on the oslospinx package, but instead use the sphinx-rtd package.
I also added the changes in the MR to update the project upstream information (homepage, watch file).
Lastly, I bumped the Standards-Version to 4.5.0.
Like I mentioned in !1 (closed), I still didn't get a change to verify this package by building another package that uses it as a dependency.