Make build order constants public

[sp-jordi-vilalta]

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Unity editor version: 2019.2.18 External Dependency Manager version: 1.2.153 Source you installed EDM (from .unitypackage or Unity Package Manager): UPM Features in External Dependency Manager in use (Android Resolver, iOS Resolver, VersionHandler, etc.): iOS Resolver Plugins SDK in use (Firebase, Admob, Facebook, etc.): Platform you are using the Unity editor on (Mac, Windows, or Linux): macOS Platform you are targeting (iOS, Android, and/or desktop): iOS Scripting Runtime (Mono, and/or IL2CPP):

Please describe the issue here:

We have some postprocess steps that modified cocoapods' input and checked the output, but these were broken with the last build order change. Could you make these constants public so we can reference them directly? For instance you could change the sample from [PostProcessBuildAttribute(45)] to something like [PostProcessBuildAttribute(IOSResolver.BUILD_ORDER_GEN_PODFILE + 1)] and you would have freedom to change the values in the future lowering the chances of breaking other 3rd party postprocessors :)

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What's the issue repro rate? (eg 100%, 1/5 etc)