Add application version info to JAR manifest

Update maven-jar-plugin configuration in spring-boot-starter-parent
with `addDefaultImplementationEntries` so that implementation versions
are included by default.

Fixes gh-2266

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

@@ -68,6 +68,7 @@
 						<archive>
 							<manifest>
 								<mainClass>${start-class}</mainClass>
+								<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
 							</manifest>
 						</archive>
 					</configuration>
@@ -93,6 +94,7 @@
 						<archive>
 							<manifest>
 								<mainClass>${start-class}</mainClass>
+								<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
 							</manifest>
 						</archive>
 					</configuration>