Bump jflex-maven-plugin from 1.9.0 to 1.9.1

Bumps [jflex-maven-plugin](https://github.com/jflex-de/jflex) from 1.9.0 to 1.9.1.
- [Release notes](https://github.com/jflex-de/jflex/releases)
- [Changelog](https://github.com/jflex-de/jflex/blob/master/RELEASE.md)
- [Commits](https://github.com/jflex-de/jflex/compare/v1.9.0...v1.9.1)

---
updated-dependencies:
- dependency-name: de.jflex:jflex-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Closes #83

Change-Id: I24bdff95217760beb18220b440fc6ea1b77ca519
diff --git a/pom.xml b/pom.xml
index 7d7ca87..31bcdcd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -167,7 +167,7 @@
             <plugin>
                 <groupId>de.jflex</groupId>
                 <artifactId>jflex-maven-plugin</artifactId>
-                <version>1.9.0</version>
+                <version>1.9.1</version>
                 <executions>
                     <execution>
                         <goals>