allow Ascii85 2.0?

[jrochkind]

The dependency gem ascii85 has had a 2.0 release.

https://github.com/DataWraith/ascii85gem/blob/master/CHANGELOG.md

It doesn't actually seem to have any breaking changes other than dropping support for old rubies?

Update pdf-reader to allow apps to install ascii85 2.0?

[yob]

Thanks, I hadn't noticed v2 was released!

I had a go, but ran into a failing spec that might indicate an unplanned behaviour change in v2. I've opened an issue to check: DataWraith/ascii85gem#8