Set up webpki-roots for android only (#327)

* Conditionally compile native or webpki roots.

* revert changes.

* Update ffi-builds.yml

.github/workflows/ffi-builds.yml

@@ -81,16 +81,19 @@ jobs:
             dylib: liblivekit_ffi.so
             target: aarch64-linux-android
             name: ffi-android-arm64
+            buildargs: --no-default-features --features "rustls-tls-webpki-roots"
           - os: ubuntu-20.04
             platform: android
             dylib: liblivekit_ffi.so
             target: armv7-linux-androideabi
             name: ffi-android-armv7
+            buildargs: --no-default-features --features "rustls-tls-webpki-roots"
           - os: ubuntu-20.04
             platform: android
             dylib: liblivekit_ffi.so
             target: x86_64-linux-android
             name: ffi-android-x86_64
+            buildargs: --no-default-features --features "rustls-tls-webpki-roots"
 
     name: Build (${{ matrix.target }})
     runs-on: ${{ matrix.os }}

livekit-ffi/Cargo.toml

@@ -7,7 +7,7 @@ description = "FFI interface for bindings in other languages"
 repository = "https://github.com/livekit/rust-sdks"
 
 [features]
-default = ["rustls-tls-webpki-roots"]
+default = ["rustls-tls-native-roots"]
 native-tls = ["livekit/native-tls"]
 native-tls-vendored = ["livekit/native-tls-vendored"]
 rustls-tls-native-roots = ["livekit/rustls-tls-native-roots"]