Dangling symlinks prevent cargo publish

[clehner]

The following files in this repo are symlinks to build artifacts:

• lib/android/didkit/src/main/jniLibs/arm64-v8a/libdidkit.so
• lib/android/didkit/src/main/jniLibs/armeabi-v7a/libdidkit.so
• lib/android/didkit/src/main/jniLibs/x86/libdidkit.so
• lib/android/didkit/src/main/jniLibs/x86_64/libdidkit.so
• lib/flutter/android/src/main/jniLibs/arm64-v8a/libdidkit.so
• lib/flutter/android/src/main/jniLibs/armeabi-v7a/libdidkit.so
• lib/flutter/android/src/main/jniLibs/x86_64/libdidkit.so
• lib/flutter/ios/libdidkit.a
• lib/flutter/libdidkit.dylib
• lib/flutter/libdidkit.so
• lib/ios/libdidkit.a

If the targets of these symlinks are not present, publishing fails, e.g.:

$ cargo publish --dry-run --manifest-path lib/Cargo.toml
    Updating crates.io index
   Packaging didkit v0.4.0 (/home/cel/src/didkit-release/lib)
error: failed to prepare local package for uploading

Caused by:
  failed to open for archiving: `/home/cel/src/didkit-release/lib/android/didkit/libs/didkit.jar`
Caused by:
  No such file or directory (os error 2)

This looks like a possible bug in cargo, since lib/Cargo.toml uses include to only include "/src", "/README.md", and "/LICENSE"; so these files should not be looked at. For now, the files can be deleted before publishing.