fix runtests.jl

Author: bicycle1885

test/runtests.jl

@@ -188,6 +188,5 @@ struct InvalidCodec <: TranscodingStreams.Codec end
 end
 
 for pkg in ["CodecZlib", "CodecBzip2", "CodecXz", "CodecZstd"]
-    Pkg.checkout(pkg, "new-protocol")
     Pkg.test(pkg)
 end