Fix build for React Native 0.69+

[short-dsb]

Summary of issue and description of fix in #91:

When React Native removed link and unlink from the CLI, they also changed two things:

1. The *.podspec file now needs to be in the root of the project.
2. A podspecPath can no longer be defined in react-native.config.js

[RashVenkat6795]

@short-dsb Getting this error, when selecting Apple Pay option.

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSDictionaryM setObject:forKey:]: object cannot be nil (key: nonce)'
*** First throw call stack:
(
    0   CoreFoundation                      0x00007ff800427378 __exceptionPreprocess + 242
    1   libobjc.A.dylib                     0x00007ff80004dbaf objc_exception_throw + 48
    2   CoreFoundation                      0x00007ff8004ae641 -[__NSCFString characterAtIndex:].cold.1 + 0
    3   CoreFoundation                      0x00007ff8004b8ed7 -[__NSDictionaryM setObject:forKey:].cold.3 + 0
    4   CoreFoundation                      0x00007ff80049b3fb -[__NSDictionaryM setObject:forKey:] + 885
    5   Boilerplate                         0x00000001065bf8cc +[RNBraintreeDropIn resolvePayment:deviceData:resolver:] + 412
    6   Boilerplate                         0x00000001065bf12a __44-[RNBraintreeDropIn show:resolver:rejecter:]_block_invoke.139 + 1642
    7   Boilerplate                         0x000000010640a043 -[BTDropInController selectionCompletedWithPaymentMethodType:nonce:error:] + 1027
    8   Boilerplate                         0x000000010641a7a5 -[BTPaymentSelectionViewController tableView:didSelectRowAtIndexPath:] + 1445
    9   UIKitCore                           0x000000011514a7e2 -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:isCellMultiSelect:deselectPrevious:performCustomSelectionAction:] + 2187
    10  UIKitCore                           0x000000011514ac19 -[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 381
    11  UIKitCore                           0x00000001154937dd -[_UIAfterCACommitBlock run] + 54
    12  UIKitCore                           0x0000000115493cdc -[_UIAfterCACommitQueue flush] + 190
    13  UIKitCore                           0x0000000114eec534 _runAfterCACommitDeferredBlocks + 782
    14  UIKitCore                           0x0000000114edace2 _cleanUpAfterCAFlushAndRunDeferredBlocks + 96
    15  UIKitCore                           0x0000000114f108dc _afterCACommitHandler + 72
    16  CoreFoundation                      0x00007ff800385fe5 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    17  CoreFoundation                      0x00007ff800380952 __CFRunLoopDoObservers + 515
    18  CoreFoundation                      0x00007ff800380e9d __CFRunLoopRun + 1161
    19  CoreFoundation                      0x00007ff800380637 CFRunLoopRunSpecific + 560
    20  GraphicsServices                    0x00007ff809c0f28a GSEventRunModal + 139
    21  UIKitCore                           0x0000000114edc425 -[UIApplication _run] + 994
    22  UIKitCore                           0x0000000114ee1301 UIApplicationMain + 123
    23  Boilerplate                         0x00000001063a9498 main + 104
    24  dyld                                0x00000001089112bf start_sim + 10
    25  ???                                 0x0000000108f53310 0x0 + 4445254416
)
libc++abi: terminating with uncaught exception of type NSException
terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSDictionaryM setObject:forKey:]: object cannot be nil (key: nonce)'

Any solution or suggestions for resolution? Thanks

[wgltony]

It's solved. Thanks