[checkstyle] Bump to 8.27

We can not bump to the latest version, due
https://github.com/checkstyle/checkstyle/issues/8248

build.gradle

@@ -409,7 +409,7 @@ subprojects {
 	apply plugin: 'org.kordamp.gradle.clirr'
 
 	checkstyle {
-		toolVersion = '8.22'
+		toolVersion = '8.27'
 	}
 	task sourcesJar(type: Jar, dependsOn: classes) {
 		classifier = 'sources'

config/checkstyle/checkstyle.xml

@@ -105,8 +105,6 @@
 		<module name="JavadocMethod">
 			<!-- TODO stricten those checks -->
 			<property name="scope" value="protected"/>
-			<property name="allowMissingJavadoc" value="true"/>
-			<property name="suppressLoadErrors" value="true"/>
 		</module>
 		<module name="JavadocStyle">
 			<property name="scope" value="public"/>