This causes issues with F-Droid, since now Posthog unconditionally references some Firebase classes, which are detected by their checks.
Note these don't do anything if Firebase messaging isn't included, which is already the case for the F-droid variant of the app.
The R8 changes should remove any code referencing Firebase in Posthog, making the offending classes unused and removing them from the final APKs.
This is not the ideal fix, that would be Posthog actually extracting these classes to an optional dependency, but it's a workaround to be able to publish F-droid versions.
* Fix warning about deprecated `keepRules.file` API
The proguard files have been moved to `app/proguard` in several directories for `common`, `foss`, and `enterprise` rules and it's those directories that are added through `keepRules.addStaticSourceDirectory(dir)`.
* Use `findPropery` instead of the deprecated `project.properties["key"]` API for `allWarningsAsErrors`
* Remove very legacy .gitignore rule and restore proguard `.keep` rules
Jorge Martin Espinosa