Bump xmlunit-matchers from 2.6.2 to 2.6.3

Bumps [xmlunit-matchers](https://github.com/xmlunit/xmlunit) from 2.6.2 to 2.6.3.
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/master/RELEASE_NOTES.md)
- [Commits](xmlunit/xmlunit@v2.6.2...v2.6.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build.gradle

@@ -167,7 +167,7 @@ dependencies {
     testCompile 'com.github.tomakehurst:wiremock:2.23.2'
     testCompile 'org.reflections:reflections:0.9.11'
     testCompile 'org.xmlunit:xmlunit-core:2.6.3'
-    testCompile 'org.xmlunit:xmlunit-matchers:2.6.2'
+    testCompile 'org.xmlunit:xmlunit-matchers:2.6.3'
     testRuntime 'com.tngtech.archunit:archunit-junit5-engine:0.10.2'
     testCompile 'com.tngtech.archunit:archunit-junit5-api:0.10.2'
     testCompile "org.testfx:testfx-core:4.0.+"