Update PHPUnit configuration schema for PHPUnit 9.3

.gitattributes

@@ -3,4 +3,5 @@
 /.travis.yml export-ignore
 /examples/ export-ignore
 /phpunit.xml.dist export-ignore
+/phpunit.xml.legacy export-ignore
 /tests/ export-ignore

.travis.yml

@@ -3,7 +3,7 @@ language: php
 # lock distro so new future defaults will not break the build
 dist: trusty
 
-matrix:
+jobs:
   include:
     - php: 5.3
       dist: precise
@@ -20,7 +20,8 @@ matrix:
     - php: hhvm-3.18
 
 install:
-  - composer install --no-interaction
+  - composer install
 
 script:
-  - vendor/bin/phpunit --coverage-text
+  - if [[ "$TRAVIS_PHP_VERSION" > "7.2" ]]; then vendor/bin/phpunit --coverage-text; fi
+  - if [[ "$TRAVIS_PHP_VERSION" < "7.3" ]]; then vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy; fi

phpunit.xml.dist

@@ -1,16 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<phpunit bootstrap="vendor/autoload.php" 
+<!-- PHPUnit configuration file with new format for PHPUnit 9.3+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
          colors="true"
          cacheResult="false">
     <testsuites>
         <testsuite name="Block React Test Suite">
             <directory>./tests/</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
+    <coverage>
+        <include>
             <directory>./src/</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
 </phpunit>

phpunit.xml.legacy

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with old format for PHPUnit 9.2 or older -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true">
+    <testsuites>
+        <testsuite name="Block React Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>