build(deps): update dependency org.codehaus.mojo:exec-maven-plugin to v3.6.1

Author: renovate-bot

benchmarks/pom.xml

@@ -126,7 +126,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
-        <version>3.5.1</version>
+        <version>3.6.1</version>
         <configuration>
           <mainClass>com.google.cloud.spanner.benchmark.LatencyBenchmark</mainClass>
           <cleanupDaemonThreads>false</cleanupDaemonThreads>