fix: cors (again), isRt flag and build in POM

mpaste/pom.xml

@@ -83,7 +83,7 @@
 			<plugin>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>
-				<version>3.2.2</version>
+				<version>${spring.boot.version}</version>
 				<executions>
 					<execution>
 						<goals>
@@ -91,10 +91,6 @@
 						</goals>
 					</execution>
 				</executions>
-				<configuration>
-					<mainClass>net.miarma.backend.mpaste.MpasteApplication</mainClass>
-					<layout>JAR</layout>
-				</configuration>
 			</plugin>
 		</plugins>
 	</build>