fix: Missing Proguard rules for R8 in full mode
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### Issue Description
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Closes: #1194

### Approach
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### TODOs before merging
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- [ ] Add tests
- [ ] Add changes to documentation (guides, repository pages, in-code descriptions)

parse/release-proguard.pro
-keepnames class com.parse.** { *; }

# Required for Parse
-keepattributes *Annotation*
-keepattributes Signature
# https://github.com/square/okio#proguard
-dontwarn okio.**

-keep @com.parse.ParseClassName class com.parse.*
-keepnames class com.parse.** { *; }
-keepclassmembers public class * extends com.parse.** {
   public <init>(...);
}

# Required for Parse
-keepattributes *Annotation*
-keepattributes Signature

# Retracing stacktraces
-keepattributes LineNumberTable,SourceFile
-renamesourcefileattribute SourceFile
Done, thanks!