Fix Windows build by adding ucrt import for math functions

Author: zamderax

Sources/CBOR/CBOR.swift

@@ -8,6 +8,8 @@ import Foundation
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif os(Windows)
+import ucrt
 #endif
 
 // MARK: - CBOR Type