WIP: Set auto update for com.tasomaniac.openwith.floss

I noticed @tasomaniac commenting on https://gitlab.com/fdroid/fdroiddata/commit/a81547e7093ed9d531c479fc892b261e466344cd#note_14062019. Seeing how comments on commits are easily lost, the question was on how to update the app on F-Droid and how the app seems to release using tags, I figured I would set up auto update mode. This is the first time I'm trying this, so I really don't know if I did it correctly. I also hope @tasomaniac can give feedback here if this would be a desirable thing.

I did notice that Build:1.0.7-floss,10700 uses commit da29b226ea1ab82c10e99a515dbb7996dc18691c. Yet, the 1.0.7 tag on the project's GitHub uses commit ac4871ea7db4f05603db49b628be8ded6db9270b. Because of this (and awaiting @tasomaniac's general feedback) I have marked the merge request WIP as I'm not sure if there is any reason for this difference (I see no maintainer notes).