Use spring boot 2.6.1 (release naming changed, no more .RELEASE)

Author: kinow

pom.xml

@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.2.2.RELEASE</version>
+		<version>2.6.1</version>
 		<relativePath/>
 	</parent>