Update dependency io.projectreactor:reactor-test to v3.7.8 (#218)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pom.xml

@@ -112,7 +112,7 @@
         <dependency>
             <groupId>io.projectreactor</groupId>
             <artifactId>reactor-test</artifactId>
-            <version>3.7.7</version>
+            <version>3.7.8</version>
             <scope>test</scope>
         </dependency>