Build bluepill and bp universal binary

[larrytaowang]

Currently we are building bluepill and bp binaries for x86_64 arch. We should build the universal binary.

With this PR now both binaries are universal

file build/Bluepill-v5.13.0-2-gf5211e8/bin/bluepill

build/Bluepill-v5.13.0-2-gf5211e8/bin/bluepill: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64:Mach-O 64-bit executable arm64]
build/Bluepill-v5.13.0-2-gf5211e8/bin/bluepill (for architecture x86_64):       Mach-O 64-bit executable x86_64
build/Bluepill-v5.13.0-2-gf5211e8/bin/bluepill (for architecture arm64):        Mach-O 64-bit executable arm64

file build/Bluepill-v5.13.0-2-gf5211e8/bin/bp

build/Bluepill-v5.13.0-2-gf5211e8/bin/bp: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64:Mach-O 64-bit executable arm64]
build/Bluepill-v5.13.0-2-gf5211e8/bin/bp (for architecture x86_64):     Mach-O 64-bit executable x86_64
build/Bluepill-v5.13.0-2-gf5211e8/bin/bp (for architecture arm64):      Mach-O 64-bit executable arm64