So if I buy v0.7, does that automatically grant me access to v0.8 and so forth?
Viewing post in Agent Horny V0.7 (Full) Standard comments
As mentioned in the page:
"Every update will be released on Itch.io as a separate project on the same day as the $5 tier patreon release. Follow my Itch.io profile to stay up to date. When you pick this option, you get the current and all previous updates. (V0.1-V0.7 Full)."
So nope, no future updates for this purchase. If you don't like the subscription basis of Patreon or purchasing individual updates on Itch, you can wait for the eventual release on Steam.