Update dependency org.codehaus.mojo:exec-maven-plugin to v3

Author: renovate[bot]

s3auth-relay/src/it/non-daemon/pom.xml

@@ -67,7 +67,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
-        <version>1.6.0</version>
+        <version>3.5.0</version>
         <executions>
           <execution>
             <id>execute-relay-JAR</id>

s3auth-relay/src/main/production/pom.xml

@@ -70,7 +70,7 @@
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
-        <version>1.6.0</version>
+        <version>3.5.0</version>
         <executions>
           <execution>
             <id>execute</id>

s3auth-rest/pom.xml

@@ -256,7 +256,7 @@
           <plugin>
             <groupId>org.codehaus.mojo</groupId>
             <artifactId>exec-maven-plugin</artifactId>
-            <version>1.6.0</version>
+            <version>3.5.0</version>
             <executions>
               <execution>
                 <id>start-takes-server</id>