public.bzl: add SKOTTIE_IOS_LIB_SDK_FRAMEWORKS

Motivation: this will let me add dependencies without breaking clients.

Change-Id: I70b71c08b0a902b2b7e6fc160c63dc3afdeb7de5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/262806
Commit-Queue: Hal Canary <halcanary@google.com>
Commit-Queue: Ben Wagner aka dogben <benjaminwagner@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
diff --git a/public.bzl b/public.bzl
index 089e98c..5353700 100644
--- a/public.bzl
+++ b/public.bzl
@@ -802,3 +802,8 @@
 SKOTTIE_IOS_LIB_HDRS = [
     "tools/skottie_ios_app/SkottieUIView.h",
 ]
+
+SKOTTIE_IOS_LIB_SDK_FRAMEWORKS = [
+    "Foundation",
+    "UIKit",
+]