Update junit5 monorepo to v5.9.1 (#11)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
diff --git a/jgvariant-parent/pom.xml b/jgvariant-parent/pom.xml
index b79b4a6..a87f2d4 100644
--- a/jgvariant-parent/pom.xml
+++ b/jgvariant-parent/pom.xml
@@ -74,7 +74,7 @@
     <google-java-format.version>1.15.0</google-java-format.version>
     <inject-resources.version>0.3.2</inject-resources.version>
     <jetbrains-annotations.version>23.1.0</jetbrains-annotations.version>
-    <junit-jupiter.version>5.9.0</junit-jupiter.version>
+    <junit-jupiter.version>5.9.1</junit-jupiter.version>
     <nullaway.version>0.10.5</nullaway.version>
     <xz.version>1.9</xz.version>
   </properties>