Avoid nightly for binding generation where possible

.. and use a particular nightly rev for where it's not.

scripts/uniffi_bindgen_generate_kotlin_android.sh

@@ -3,15 +3,15 @@ BINDINGS_DIR="bindings/kotlin"
 TARGET_DIR="target"
 PROJECT_DIR="ldk-node-android"
 PACKAGE_DIR="org/lightningdevkit/ldknode"
-UNIFFI_BINDGEN_BIN="cargo +nightly run --features=uniffi/cli --bin uniffi-bindgen"
+UNIFFI_BINDGEN_BIN="cargo run --features=uniffi/cli --bin uniffi-bindgen"
 ANDROID_NDK_ROOT="/opt/homebrew/share/android-ndk"
 LLVM_ARCH_PATH="darwin-x86_64"
 PATH="$ANDROID_NDK_ROOT/toolchains/llvm/prebuilt/$LLVM_ARCH_PATH/bin:$PATH"
 
-rustup +nightly target add x86_64-linux-android aarch64-linux-android armv7-linux-androideabi
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER="x86_64-linux-android21-clang" CC="x86_64-linux-android21-clang" cargo +nightly build --profile release-smaller --features uniffi --target x86_64-linux-android || exit 1
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER="armv7a-linux-androideabi21-clang" CC="armv7a-linux-androideabi21-clang" cargo +nightly build --profile release-smaller --features uniffi --target armv7-linux-androideabi || exit 1
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo +nightly build --profile release-smaller --features uniffi --target aarch64-linux-android || exit 1
+rustup target add x86_64-linux-android aarch64-linux-android armv7-linux-androideabi
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER="x86_64-linux-android21-clang" CC="x86_64-linux-android21-clang" cargo build --profile release-smaller --features uniffi --target x86_64-linux-android || exit 1
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER="armv7a-linux-androideabi21-clang" CC="armv7a-linux-androideabi21-clang" cargo build --profile release-smaller --features uniffi --target armv7-linux-androideabi || exit 1
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo build --profile release-smaller --features uniffi --target aarch64-linux-android || exit 1
 $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language kotlin -o "$BINDINGS_DIR"/"$PROJECT_DIR"/lib/src/main/kotlin || exit 1
 
 JNI_LIB_DIR="$BINDINGS_DIR"/"$PROJECT_DIR"/lib/src/main/jniLibs/ 

scripts/uniffi_bindgen_generate_python.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 BINDINGS_DIR="./bindings/python"
-UNIFFI_BINDGEN_BIN="cargo +nightly run --features=uniffi/cli --bin uniffi-bindgen"
+UNIFFI_BINDGEN_BIN="cargo run --features=uniffi/cli --bin uniffi-bindgen"
 
-cargo +nightly build --release --features uniffi || exit 1
+cargo build --release --features uniffi || exit 1
 $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language python -o "$BINDINGS_DIR" || exit 1
 cp ./target/release/libldk_node.dylib "$BINDINGS_DIR"/libldk_node.dylib || exit 1

scripts/uniffi_bindgen_generate_swift.sh

@@ -8,10 +8,10 @@ $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language swift -o "$BINDING
 mkdir -p $BINDINGS_DIR
 
 # Install rust target toolchains
-rustup install nightly-x86_64-apple-darwin
-rustup component add rust-src --toolchain nightly-x86_64-apple-darwin
+rustup install nightly-2023-04-10
+rustup component add rust-src --toolchain nightly-2023-04-10
 rustup target add aarch64-apple-ios x86_64-apple-ios
-rustup target add aarch64-apple-ios-sim --toolchain nightly
+rustup target add aarch64-apple-ios-sim --toolchain nightly-2023-04-10
 rustup target add aarch64-apple-darwin x86_64-apple-darwin
 
 # Build rust target libs
@@ -20,7 +20,7 @@ cargo build --profile release-smaller --features uniffi --target x86_64-apple-da
 cargo build --profile release-smaller --features uniffi --target aarch64-apple-darwin || exit 1
 cargo build --profile release-smaller --features uniffi --target x86_64-apple-ios || exit 1
 cargo build --profile release-smaller --features uniffi --target aarch64-apple-ios || exit 1
-cargo +nightly build --release --features uniffi --target aarch64-apple-ios-sim || exit 1
+cargo +nightly-2023-04-10 build --release --features uniffi --target aarch64-apple-ios-sim || exit 1
 
 # Combine ios-sim and apple-darwin (macos) libs for x86_64 and aarch64 (m1)
 mkdir -p target/lipo-ios-sim/release-smaller || exit 1