Update to cfg-if 1.0

Cargo.toml

@@ -15,7 +15,7 @@ travis-ci = { repository = "rust-random/getrandom" }
 appveyor = { repository = "rust-random/getrandom" }
 
 [dependencies]
-cfg-if = "0.1.2"
+cfg-if = "1"
 
 # When built as part of libstd
 compiler_builtins = { version = "0.1", optional = true }