[master] fb159a3fd Bump osx image version

[Federico G. Schwindt]

commit fb159a3fde67af97e7f3cebfcc1029db1718c1db
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Sun May 10 20:46:25 2020 +0100

    Bump osx image version

diff --git a/.travis.yml b/.travis.yml
index a68713459..ac097fe8b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -74,7 +74,7 @@ jobs:
         - ./configure --with-unwind --enable-developer-warnings --enable-debugging-symbols --disable-stack-protector --with-persistent-storage --enable-asan --enable-ubsan
     - stage: test
       os: osx
-      osx_image: xcode11.3
+      osx_image: xcode11.4
       compiler: clang
       addons:
         homebrew: