Fix BindableState: Codable strategies (#781)

Author: stephencelis

Sources/ComposableArchitecture/SwiftUI/Binding.swift

@@ -205,13 +205,23 @@
 
   extension BindableState: Decodable where Value: Decodable {
     public init(from decoder: Decoder) throws {
-      self.init(wrappedValue: try Value(from: decoder))
+      do {
+        let container = try decoder.singleValueContainer()
+        self.init(wrappedValue: try container.decode(Value.self))
+      } catch {
+        self.init(wrappedValue: try Value(from: decoder))
+      }
     }
   }
 
   extension BindableState: Encodable where Value: Encodable {
     public func encode(to encoder: Encoder) throws {
-      try self.wrappedValue.encode(to: encoder)
+      do {
+        var container = encoder.singleValueContainer()
+        try container.encode(self.wrappedValue)
+      } catch {
+        try self.wrappedValue.encode(to: encoder)
+      }
     }
   }