enable build on OpenJDK-15 by bumping to

maven-enforcer-plugin-3.0.0-M3
jacoco-maven-plugin-0.8.6

Author: axtimwalde

pom.xml

@@ -236,7 +236,7 @@
 		<maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
 		<maven-dependency-plugin.version>3.1.2</maven-dependency-plugin.version>
 		<maven-deploy-plugin.version>2.8.2</maven-deploy-plugin.version>
-		<maven-enforcer-plugin.version>1.4.1</maven-enforcer-plugin.version>
+		<maven-enforcer-plugin.version>3.0.0-M3</maven-enforcer-plugin.version>
 		<maven-failsafe-plugin.version>2.22.2</maven-failsafe-plugin.version>
 		<maven-gpg-plugin.version>1.6</maven-gpg-plugin.version>
 		<maven-install-plugin.version>2.5.2</maven-install-plugin.version>
@@ -265,7 +265,7 @@
 		<dokka-maven-plugin.version>0.9.18</dokka-maven-plugin.version>
 		<formatter-maven-plugin.version>2.11.0</formatter-maven-plugin.version>
 		<impsort-maven-plugin.version>1.3.2</impsort-maven-plugin.version>
-		<jacoco-maven-plugin.version>0.8.5</jacoco-maven-plugin.version>
+		<jacoco-maven-plugin.version>0.8.6</jacoco-maven-plugin.version>
 		<javafx-maven-plugin.version>8.8.3</javafx-maven-plugin.version>
 		<maven-graph-plugin.version>1.45</maven-graph-plugin.version>
 		<nexus-staging-maven-plugin.version>1.6.8</nexus-staging-maven-plugin.version>