update the travis CI spec

.travis.yml

@@ -1,32 +1,13 @@
-language: swift
+language: objective-c
+osx_image: xcode13.2
 branches:
   only:
     - master
-matrix:
-  include:
-    - name: "macOS"
-      os: osx
-      osx_image: xcode13.2
-      script: xcrun xcodebuild -project TweetNacl.xcodeproj -scheme TweetNacl-macOS test | xcpretty
-    - name: "iOS"
-      os: osx
-      osx_image: xcode13.2
-      script: xcrun xcodebuild -project TweetNacl.xcodeproj -scheme TweetNacl-iOS test | xcpretty
-    - name: "watchOS"
-      os: osx
-      osx_image: xcode13.2
-      script: xcrun xcodebuild -project TweetNacl.xcodeproj -scheme TweetNacl-watchOS test | xcpretty
-    - name: "tvOS"
-      os: osx
-      osx_image: xcode13.2
-      script: xcrun xcodebuild -project TweetNacl.xcodeproj -scheme TweetNacl-tvOS test | xcpretty
-    # - name: "linux"
-    #   os: linux
-    #   env: swift=5.5
-    #   install: 
-    #   - curl "https://swift.org/builds/swift-${swift}-release/ubuntu1604/swift-${swift}-RELEASE/swift-${swift}-RELEASE-ubuntu16.04.tar.gz" > /tmp/swift.tar.gz
-    #   - tar -xzf /tmp/swift.tar.gz -C /tmp
-    #   - export PATH="${PATH}:/tmp/swift-${swift}-RELEASE-ubuntu16.04/usr/bin"
-    #   - swift -version
-    #   script: swift test
+
+before_install:
+  - gem install xcpretty
+
+script:
+- swift build
+- swift test
 after_success: bash <(curl -s https://codecov.io/bash)