Bump xcode version in travis

RangerMauve · RangerMauve · commit ed0da7a27283 · 2020-07-20T20:50:24.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -24,7 +24,7 @@ jobs:
     - stage: Deploy Windows & Mac
       if: tag IS present
       os: osx
-      osx_image: xcode10.1
+      osx_image: xcode10.15
       script:
         - npm run build -- --mac --win -p always
       before_cache:
