pidgin/pidgin

6d79c7cf9699
add flatpak manifests for both pidgin and finch

Add flatpaks for both pidgin3 and finch3

Testing Done:
Ran both and then seem okay. The mercurial dependency is to make sure we have the correct revision in the about dialog.

Reviewed at https://reviews.imfreedom.org/r/67/
[wrap-hg]
directory = talkatu
url = https://keep.imfreedom.org/talkatu/talkatu
revision = default