Try resolving package dependencies first

This additional step generate .swiftpm which hopefully resolves the
'could not generate PIF' issue.

Author: crazytonyli

fastlane/Fastfile

@@ -5,6 +5,10 @@ default_platform(:ios)
 platform :ios do
   desc 'Builds the project and runs tests'
   lane :test do
+    xcodebuild(
+      scheme: 'WordPressShared',
+      xcargs: '-resolvePackageDependencies'
+    )
     run_tests(
       package_path: '.',
       scheme: 'WordPressShared',