Fix new warning caused by Swift 5.3 and bring SwiftLint rule in sync with it

.swiftlint.yml

@@ -212,3 +212,5 @@ closure_body_length:
   error: 60
 type_name:
   max_length: 50
+trailing_closure:
+  only_single_muted_parameter: true

.travis.yml

@@ -1,5 +1,5 @@
 language: objective-c
-osx_image: xcode11.6
+osx_image: xcode12
 addons:
   homebrew:
     packages:

pass.xcodeproj/xcshareddata/xcschemes/pass.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1100"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

pass/Controllers/GitRepositorySettingsTableViewController.swift

@@ -33,6 +33,7 @@ class GitRepositorySettingsTableViewController: UITableViewController, PasswordA
             keyStore: keychain
         )
     }
+
     private var gitAuthenticationMethod: GitAuthenticationMethod {
         get { Defaults.gitAuthenticationMethod }
         set {

pass/Controllers/PasswordDetailTableViewController.swift

@@ -88,9 +88,9 @@ class PasswordDetailTableViewController: UITableViewController, UIGestureRecogni
     @objc
     private func decryptThenShowPassword(keyID: String? = nil) {
         guard let passwordEntity = passwordEntity else {
-            Utils.alert(title: "CannotShowPassword".localize(), message: "PasswordDoesNotExist".localize(), controller: self) {
+            Utils.alert(title: "CannotShowPassword".localize(), message: "PasswordDoesNotExist".localize(), controller: self, completion: {
                 self.navigationController!.popViewController(animated: true)
-            }
+            })
             return
         }
         DispatchQueue.global(qos: .userInitiated).async {