Don't install ext-libevent on PHP 7.3

WyriHaximus · WyriHaximus · commit 79429c76be87 · 2018-11-11T22:36:20.000+01:00
diff --git a/travis-init.sh b/travis-init.sh
@@ -15,7 +15,8 @@ if [[ "$TRAVIS_PHP_VERSION" != "hhvm" &&
     # install 'libevent' PHP extension (does not support php 7)
     if [[ "$TRAVIS_PHP_VERSION" != "7.0" &&
           "$TRAVIS_PHP_VERSION" != "7.1" &&
-          "$TRAVIS_PHP_VERSION" != "7.2" ]]; then
+          "$TRAVIS_PHP_VERSION" != "7.2"  &&
+          "$TRAVIS_PHP_VERSION" != "7.3" ]]; then
         curl http://pecl.php.net/get/libevent-0.1.0.tgz | tar -xz
         pushd libevent-0.1.0
         phpize
