Synthesize Equatable conformance for Signature

.swiftlint.yml

@@ -52,6 +52,7 @@ opt_in_rules:
   - redundant_nil_coalescing
   - redundant_type_annotation
   - sorted_first_last
+  - static_operator
   - strict_fileprivate
   - switch_case_on_newline
   - toggle_bool

SwiftGit2/Objects.swift

@@ -83,13 +83,6 @@ extension Signature: Hashable {
 	}
 }
 
-public func == (lhs: Signature, rhs: Signature) -> Bool {
-	return lhs.name == rhs.name
-		&& lhs.email == rhs.email
-		&& lhs.time == rhs.time
-		&& lhs.timeZone == rhs.timeZone
-}
-
 /// A git commit.
 public struct Commit: ObjectType, Hashable {
 	public static let type = GIT_OBJ_COMMIT