Update API URL to circumvent block in Egypt

[iSWORD]

It appears that subdomains of onesignal.com are not blocked by the Egyptian ISP TE Data (also known as WE)

Fixes #554 & #545

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This change is 

[iSWORD]

@mikechoch @jkasten2

Same as OneSignal/OneSignal-Android-SDK#924 (comment)

[mikechoch]

@iSWORD Are you still experiencing OneSignal being blocked in Egypt? This should be fixed already, no need to modify the URL this would only be a temporary fix any way.

[iSWORD]

It's not fixed yet unfortunately. I understand this is temporary, but it works fine.

[mikechoch]

Well sadly we can't merge a PR if this is simply a temporary fix, but you should not be experiencing any blocking so we will investigate this.

Are you using any apps that might have a blacklist to block specific URLs? We had one customer with a rooted Android device that had an ad blocker with root privileges. This ended being the cause of onesignal.com being blocked.

[iSWORD]

It doesn't work on any of my devices. This fix might be temporary in a way that Egypt may block subdomains of OneSignal.com at some point, but it's not something that will break any functionality for other people, so merging it shouldn't be a problem.

[mikechoch]

I understand, but we will not be changing the URL we use in our SDK. This should remain the same and we will look into getting Egypt up and running again if it is truly blocked.

I will be closing this PR now.

[iSWORD]

That's a bummer. I don't see how changing the URL to a first party alias could cause any problems but you're the maintainer so what do I know. I have no other choice but to use SNS to meet our SLAs though because my clients will ask for an action plan with a clear timeline.

Thank you & good luck getting TE Data to unblock your domain :)

[Kaabi]

I understand, but we will not be changing the URL we use in our SDK. This should remain the same and we will look into getting Egypt up and running again if it is truly blocked.

I will be closing this PR now.

Moving to Firebase directly or Amazon SNS like @iSWORD mentioned is the best solution for a problem exists since August 2019 and only been noticeable in October 2019.

adding an argument to OneSignal init function to change base_url seem to be something you won't even wanna think about it.

[muhammad-omar]

@mikechoch We can understand the size and impact proposed here along with the affected users.
However, it is actually affecting almost all of us here in Egypt and it is not 100% consistently blocked. Maybe 2 out of 10 trials passes. Also, ISPs claims that they did not block it, so it is no luck with asking them to allow it.

We can check possible solutions like passing variables while installing the plugin with default settings to be the current one. maybe pass one of predefined list while installing to ensure more secure approach avoiding random URLs (ex. --USE_APP_SUBDOMAIN="true")

[jkasten2]

The change to use api.onesignal.com is now included in the release 2.13.0

https://github.com/OneSignal/OneSignal-iOS-SDK/releases/tag/2.13.0

[Kaabi]

The change to use api.onesignal.com is now included in the release 2.13.0

https://github.com/OneSignal/OneSignal-iOS-SDK/releases/tag/2.13.0

this is great news.
when OneSignal-Cordova-SDK will include the new SDK updates?