Match formatting used by Xcode. Turns out Xcode requires two digits for hex colors values. Single digits get repeated.

Sources/LibMakeColors/Generators/AssetCatalogGenerator.swift

@@ -67,10 +67,10 @@ private extension Color {
             "color" : {
                 "color-space" : "srgb",
                 "components" : {
-                "alpha" : "0x\(String(alpha, radix: 16))",
+                "alpha" : "\(Double(alpha) / 0xFF)",
-                "blue" : "0x\(String(blue, radix: 16))",
+                "blue" : "0x\(blue, radix: 16, width: 2)",
-                "green" : "0x\(String(green, radix: 16))",
+                "green" : "0x\(green, radix: 16, width: 2)",
-                "red" : "0x\(String(red, radix: 16))"
+                "red" : "0x\(red, radix: 16, width: 2)"
                 }
             },
             "idiom" : "universal"
@@ -88,6 +88,22 @@ private extension Color {
     }
 }
 
+extension String.StringInterpolation {
+    mutating func appendInterpolation<I: BinaryInteger>(
+        _ value: I,
+        radix: Int,
+        width: Int = 0,
+        uppercase: Bool = true
+    ) {
+        var string = String(value, radix: radix, uppercase: uppercase)
+        if width > string.count {
+            string.insert(contentsOf: String(repeating: "0", count: width - string.count), at: string.startIndex)
+        }
+
+        appendLiteral(string)
+    }
+}
+
 private let group = """
 {
   "properties" : {