Upgrade to Maven War Plugin 3.1.0

Closes gh-9344

spring-boot-dependencies/pom.xml

@@ -212,7 +212,7 @@
 		<maven-site-plugin.version>3.5.1</maven-site-plugin.version>
 		<maven-source-plugin.version>3.0.1</maven-source-plugin.version>
 		<maven-surefire-plugin.version>2.18.1</maven-surefire-plugin.version>
-		<maven-war-plugin.version>2.6</maven-war-plugin.version>
+		<maven-war-plugin.version>3.1.0</maven-war-plugin.version>
 		<versions-maven-plugin.version>2.3</versions-maven-plugin.version>
 	</properties>
 	<dependencyManagement>

spring-boot-parent/pom.xml

@@ -580,9 +580,6 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-war-plugin</artifactId>
-				<configuration>
-					<failOnMissingWebXml>false</failOnMissingWebXml>
-				</configuration>
 			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>

spring-boot-starters/spring-boot-starter-parent/pom.xml

@@ -104,7 +104,6 @@
 					<groupId>org.apache.maven.plugins</groupId>
 					<artifactId>maven-war-plugin</artifactId>
 					<configuration>
-						<failOnMissingWebXml>false</failOnMissingWebXml>
 						<archive>
 							<manifest>
 								<mainClass>${start-class}</mainClass>

spring-boot-tools/spring-boot-loader/src/it/executable-war/pom.xml

@@ -33,7 +33,6 @@
 							<Start-Class>org.springframework.boot.load.it.war.embedded.EmbeddedWarStarter</Start-Class>
 						</manifestEntries>
 					</archive>
-					<failOnMissingWebXml>false</failOnMissingWebXml>
 				</configuration>
 			</plugin>
 			<plugin>

spring-boot-tools/spring-boot-maven-plugin/src/it/war-reactor/war/pom.xml

@@ -29,7 +29,6 @@
 				<artifactId>maven-war-plugin</artifactId>
 				<version>@maven-war-plugin.version@</version>
 				<configuration>
-					<failOnMissingWebXml>false</failOnMissingWebXml>
 					<archive>
 						<manifestEntries>
 							<Not-Used>Foo</Not-Used>

spring-boot-tools/spring-boot-maven-plugin/src/it/war-with-unpack/pom.xml

@@ -38,7 +38,6 @@
 				<artifactId>maven-war-plugin</artifactId>
 				<version>@maven-war-plugin.version@</version>
 				<configuration>
-					<failOnMissingWebXml>false</failOnMissingWebXml>
 					<archive>
 						<manifestEntries>
 							<Not-Used>Foo</Not-Used>

spring-boot-tools/spring-boot-maven-plugin/src/it/war/pom.xml

@@ -30,7 +30,6 @@
 				<artifactId>maven-war-plugin</artifactId>
 				<version>@maven-war-plugin.version@</version>
 				<configuration>
-					<failOnMissingWebXml>false</failOnMissingWebXml>
 					<archive>
 						<manifestEntries>
 							<Not-Used>Foo</Not-Used>