Missing ProGuard rules

[ag2s20150909]

https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/cronet/android/

[ag2s20150909]

# Keep all of Cronet API as it's used by the Cronet module.
-keep public class org.chromium.net.* {
    !private *;
    *;
}