Upgrade build plugin versions.

Closes #205

Author: mp911de

bom-client/pom.xml

@@ -40,7 +40,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-dependency-plugin</artifactId>
-				<version>3.5.0</version>
+				<version>3.6.1</version>
 				<executions>
 					<execution>
 						<id>purge-local-repository</id>

bom/pom.xml

@@ -192,7 +192,7 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>flatten-maven-plugin</artifactId>
-				<version>1.4.1</version>
+				<version>1.6.0</version>
 				<executions>
 					<execution>
 						<id>flatten</id>
@@ -237,7 +237,7 @@
 						<plugin>
 							<groupId>org.jfrog.buildinfo</groupId>
 							<artifactId>artifactory-maven-plugin</artifactId>
-							<version>3.6.1</version>
+							<version>3.6.2</version>
 							<executions>
 								<execution>
 									<id>build-info</id>
@@ -336,7 +336,7 @@
 						<plugin>
 							<groupId>org.apache.maven.plugins</groupId>
 							<artifactId>maven-gpg-plugin</artifactId>
-							<version>3.0.1</version>
+							<version>3.1.0</version>
 							<executions>
 								<execution>
 									<id>sign-artifacts</id>
@@ -360,7 +360,7 @@
 						<plugin>
 							<groupId>org.apache.maven.plugins</groupId>
 							<artifactId>maven-enforcer-plugin</artifactId>
-							<version>3.3.0</version>
+							<version>3.4.1</version>
 							<executions>
 								<execution>
 									<id>enforce-release-rules</id>