feat: integration feature flags

[Kiruel]

This PR will fix #14

This PR need to have:

• [x] A new release for https://github.com/PostHog/posthog-ios , currently only available in master.
• [x] Same for android https://github.com/PostHog/posthog-android.

WIP:

• [x] Android integration
  • [x] isFeatureEnabled
  • [x] reloadFeatureFlags
• [x] iOS integration
  • [x] isFeatureEnabled
  • [x] reloadFeatureFlags
• [x] Web integration
  • [x] isFeatureEnabled
  • [x] reloadFeatureFlags

Slack thread

[aylton-almeida]

Is there any update on this? I'd like to help somehow if possible.

[Kiruel]

Hi @aylton-almeida , I would like to continue this task but I need some time. Probably next week I will keep working on it.

[joethreepwood]

@neilkakkar @fuziontech Just wanted to follow up on this and see where we stand?

[Kiruel]

@joethreepwood We should be good for a review now, android version is 2.0.0.

[neilkakkar]

Hey @Kiruel , thanks for the contribution! Sorry this is taking ages to review (it's not usual at PostHog). It's happening here because we don't have flutter knowledge and need someone to get up to speed so we can review 😅

[neilkakkar]

But, the good news is that since all dependencies here are now complete, we're prioritising this, so you should definitely have a review by next week!

[Kiruel]

@neilkakkar Hi, anynews ?

[Kiruel]

I just update the branch to fix conflict, ready to be merged. @liyiy or @joethreepwood .

[liyiy]

awesome! @Kiruel would you like to update the changelog and release for this too?

[Kiruel]

Thanks @liyiy for your time on this one ! I already change the changelog for the documentation, and I think I don't have the right to create a release.