Fix @retroactive break older Swift compiler support issue

See https://github.com/swiftlang/swift-evolution/blob/main/proposals/0364-retroactive-conformance-warning.md#source-compatibility

Author: Kyle-Ye

Sources/OpenGraph/Attribute/Attribute/OGAttribute.swift

@@ -78,7 +78,7 @@ extension OGAttribute {
 
 // MARK: CustomStringConvertible
 
-extension OGAttribute: @retroactive CustomStringConvertible {
+extension OGAttribute: Swift.CustomStringConvertible {
     @inlinable
     public var description: String { "#\(rawValue)" }
 }

Sources/OpenGraph/Attribute/Weak/OGWeakAttribute.swift

@@ -35,7 +35,7 @@ extension OGWeakAttribute {
     }
 }
 
-extension OGWeakAttribute: @retroactive Hashable {
+extension OGWeakAttribute: Swift.Hashable {
     @_alwaysEmitIntoClient
     public static func == (lhs: OGWeakAttribute, rhs: OGWeakAttribute) -> Bool {
         lhs.raw_attribute == rhs.raw_attribute && lhs.subgraph_id == rhs.subgraph_id
@@ -53,7 +53,7 @@ extension OGWeakAttribute: @retroactive Hashable {
     }
 }
 
-extension OGWeakAttribute: @retroactive CustomStringConvertible {
+extension OGWeakAttribute: Swift.CustomStringConvertible {
     @_alwaysEmitIntoClient
     public var description: String { attribute?.description ?? "nil" }
 }

Sources/OpenGraph/Runtime/OGTypeID.swift

@@ -23,7 +23,7 @@ public func OGTypeApplyFields2(
     body: (UnsafePointer<Int8>, Int, Any.Type) -> Bool
 ) -> Bool
 
-extension OGTypeID: @retroactive Hashable, @retroactive CustomStringConvertible {
+extension OGTypeID: Swift.Hashable, Swift.CustomStringConvertible {
     @inlinable
     @inline(__always)
     public init(_ type: Any.Type) {