Upgrade build plugins.

Closes #130

Author: mp911de

bom/pom.xml

@@ -293,7 +293,7 @@
 						<plugin>
 							<groupId>org.apache.maven.plugins</groupId>
 							<artifactId>maven-gpg-plugin</artifactId>
-							<version>1.6</version>
+							<version>3.0.1</version>
 							<executions>
 								<execution>
 									<id>sign-artifacts</id>
@@ -365,7 +365,7 @@
 						<plugin>
 							<groupId>org.apache.maven.plugins</groupId>
 							<artifactId>maven-enforcer-plugin</artifactId>
-							<version>3.0.0</version>
+							<version>3.2.1</version>
 							<executions>
 								<execution>
 									<id>enforce-release-rules</id>

pom.xml

@@ -76,7 +76,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-install-plugin</artifactId>
-				<version>3.0.0-M1</version>
+				<version>3.1.0</version>
 				<configuration>
 					<skip>true</skip>
 				</configuration>
@@ -85,7 +85,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-deploy-plugin</artifactId>
-				<version>3.0.0-M1</version>
+				<version>3.1.0</version>
 				<configuration>
 					<skip>true</skip>
 				</configuration>