Fix failing builds on Travis CI

- Use CocoaPods CDN for faster build times
- Update ruby version to 2.7.1
- Fix a failing unit test

.ruby-version

@@ -1 +1 @@
-2.3.0
+2.7.1

.travis.yml

@@ -1,26 +1,10 @@
 language: objective-c
+osx_image: xcode11.3
+
 cache:
-  - bundler
-  - cocoapods
-osx_image: xcode7.3
-
-before_install:
-  - brew update || brew update
-  - brew outdated xctool || brew upgrade xctool
-  - SIMULATOR_ID=$(xcrun instruments -s | grep -o "iPhone 6 (9.3) \[.*\]" | grep -o "\[.*\]" | sed "s/^\[\(.*\)\]$/\1/")
-
-install:
-  - bundle install
-  - bundle exec pod install
+  bundler: true
+  cocoapods: true
 
 script:
-  - echo $SIMULATOR_ID
-  # Launching the simulator before building and testing is necessary to prevent spurious timeouts.
-  # Specifying the simulator UDID is also necessary.
-  - open -a "Simulator" --args -CurrentDeviceUDID $SIMULATOR_ID
-  - travis_wait bundle exec rake spec:unit
-  - bundle exec rake spec:api:integration
+  - set -o pipefail && xcodebuild -workspace BraintreeDropIn.xcworkspace -scheme UnitTests -destination platform\=iOS\ Simulator,OS\=13.3,name\=iPhone\ 11 test | bundle exec xcpretty -c
 
-notifications:
-  email:
-    - team-ios@getbraintree.com

Podfile

@@ -1,4 +1,4 @@
-source 'https://github.com/CocoaPods/Specs.git'
+source 'https://cdn.cocoapods.org/'
 
 platform :ios, '9.0'
 inhibit_all_warnings!

UnitTests/BTUIKAppearanceTests.swift

@@ -68,7 +68,7 @@ class BTUIKAppearanceTests: XCTestCase {
             XCTAssertEqual(appearance?.font, UIFont.systemFont(ofSize:10));
             XCTAssertEqual(appearance?.boldFont, UIFont.boldSystemFont(ofSize:10));
             XCTAssertEqual(appearance?.useBlurs, true);
-            XCTAssertEqual(appearance?.postalCodeFormFieldKeyboardType, .numberPad);
+            XCTAssertEqual(appearance?.postalCodeFormFieldKeyboardType, .default);
 
             XCTAssertEqual(appearance?.barBackgroundColor, UIColor.systemBackground)
             XCTAssertEqual(appearance?.formBackgroundColor, UIColor.systemGroupedBackground);