Enable codegen in RNTester's NativeModuleExample

Summary:
Create a ScreenshotManager.podspec (codegen recipe included) and add ScreenshotManager Pod to the Podfile.

Changelog:
[Internal]

Reviewed By: fkgozali

Differential Revision: D30623054

fbshipit-source-id: be20880a53ba8a08f8b42b8d81c868c8a21960e1

packages/rn-tester/NativeModuleExample/ScreenshotManager.podspec

@@ -0,0 +1,39 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+require "json"
+
+package = JSON.parse(File.read(File.join(__dir__, "../package.json")))
+
+folly_compiler_flags = '-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -Wno-comma -Wno-shorten-64-to-32'
+folly_version = '2021.06.28.00'
+
+Pod::Spec.new do |s|
+  s.name            = "ScreenshotManager"
+  s.version         = package["version"]
+  s.summary         = package["description"]
+  s.description     = "ScreenshotManager"
+  s.homepage        = "https://github.com/facebook/react-native.git"
+  s.license         = "MIT"
+  s.platforms       = { :ios => "11.0", :tvos => "11.0" }
+  s.compiler_flags  = folly_compiler_flags + ' -Wno-nullability-completeness'
+  s.author          = "Facebook, Inc. and its affiliates"
+  s.source          = { :git => "https://github.com/facebook/react-native.git", :tag => "#{s.version}" }
+
+  s.source_files    = "**/*.{h,m,mm,swift}"
+  s.requires_arc    = true
+
+  s.dependency "React"
+  s.dependency "RCT-Folly", folly_version
+
+  # s.dependency "..."
+
+  # Enable codegen for this library
+  use_react_native_codegen!(s, {
+    :react_native_path => "../../..",
+    :js_srcs_dir => "./",
+    :output_dir => "./"
+  })
+end