Add support for critical alerts

[Mstrodl]

Description

• Adds critical alert support (See Apple's docs)
• Allows for custom Serialize implementations for the APNS payload. This means users can add custom fields inside the aps key (a bad idea for new software, but unfortunately we're kinda stuck with old apps that read custom data from weird places)

How Has This Been Tested?

• cargo test passes
• Have been successfully sending pushes to our app with critical alerts and custom keys in aps.

Due Dilligence

Not sure if I'm filling these out correctly:

• [x] Breaking change (Users need to import PayloadLike. Maybe we could have dummy functions that replicate the functionality on the struct itself? Not sure if that'll work or if it's worth doing though)
• [x] Requires a documentation update (I believe I did this, so not sure if I should check it or not)
• [x] Requires a e2e/integration test update (Same as above)

Would really love for someone to code review this and let me know if there's anything I can improve on!

[Mstrodl]

@HarryET Bumping this, since it seems like you're the maintainer

[HarryET]

@HarryET Bumping this, since it seems like you're the maintainer

Hey @Mstrodl, yeah I'm maintaining it! I'm OOO for the rest of this week but will do a proper review next week, thanks for the PR 😄

[Mstrodl]

@HarryET Made some changes... Let me know what you think!

[HarryET]

@HarryET Made some changes... Let me know what you think!

Very nice, makes .set_critical() easier to read, do we have tests for that custom serde seralizer/deseralizer?

[Mstrodl]

@HarryET Made some changes... Let me know what you think!

Very nice, makes .set_critical() easier to read, do we have tests for that custom serde seralizer/deseralizer?

Yes, because everything goes through PayloadLike, there shouldn't be any difference. I also have an example of the full thing in the docs, but it's not run automatically because it would need credentials

[HarryET]

@HarryET Made some changes... Let me know what you think!

Very nice, makes .set_critical() easier to read, do we have tests for that custom serde seralizer/deseralizer?

Yes, because everything goes through PayloadLike, there shouldn't be any difference. I also have an example of the full thing in the docs, but it's not run automatically because it would need credentials

Okay, a small test case might be nice but if it's already included by proxy that should be ok

[Mstrodl]

Any news on those reviews?