Update to latest Spring Data Commons and Spring Boot RCs.

This commit closes #40 by updating Spring Data Commons to RC3 and Spring Boot to M6. It also drops management of Kotlin and Project Reactor dependencies. Instead, it relies on the management done by Spring Data Commons in RC3.

Furthermore, it restores convergences between the dependencies of Spring Data R2DBC and R2DBC-H2 by using R2DBC’s bom as well.

README.adoc

@@ -7,7 +7,7 @@
 :artifactId: spring-data-neo4j-rx
 :artifactIdStarter: spring-data-neo4j-rx-spring-boot-starter
 :neo4j_version: 4.0.0-alpha09
-:spring-boot_version: 2.2.0.M5
+:spring-boot_version: 2.2.0.M6
 // end::versions[]
 
 image:https://img.shields.io/maven-central/v/org.neo4j.springframework.data/spring-data-neo4j-rx.svg[Maven Central,link=http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22org.neo4j.springframework.data%22%20AND%20a%3A%22spring-data-neo4j-rx%22]

pom.xml

@@ -23,7 +23,7 @@
 	<parent>
 		<groupId>org.springframework.data.build</groupId>
 		<artifactId>spring-data-parent</artifactId>
-		<version>2.2.0.RC1</version>
+		<version>2.2.0.RC3</version>
 	</parent>
 
 	<groupId>org.neo4j.springframework.data</groupId>
@@ -104,13 +104,13 @@
 		<neo4j-java-driver.version>4.0.0-beta01</neo4j-java-driver.version>
 		<neo4j.version>3.5.8</neo4j.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<r2dbc.releasetrain>Arabba-BUILD-SNAPSHOT</r2dbc.releasetrain>
 		<reactive-streams.version>1.2.1</reactive-streams.version>
-		<reactor-bom.version>Californium-SR4</reactor-bom.version>
 		<revision>1.0.0</revision>
 		<rxjava.version>1.3.8</rxjava.version>
 		<rxjava2.version>2.2.5</rxjava2.version>
 		<sha1></sha1>
-		<springdata-commons.version>2.2.0.RC1</springdata-commons.version>
+		<springdata-commons.version>2.2.0.RC3</springdata-commons.version>
 		<testcontainers.version>1.10.7</testcontainers.version>
 
 		<skipUnitTests>${skipTests}</skipUnitTests>
@@ -124,13 +124,6 @@
 
 	<dependencyManagement>
 		<dependencies>
-			<dependency>
-				<groupId>io.projectreactor</groupId>
-				<artifactId>reactor-bom</artifactId>
-				<version>${reactor-bom.version}</version>
-				<type>pom</type>
-				<scope>import</scope>
-			</dependency>
 			<dependency>
 				<groupId>io.reactivex</groupId>
 				<artifactId>rxjava</artifactId>
@@ -164,6 +157,13 @@
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
+			<dependency>
+				<groupId>io.r2dbc</groupId>
+				<artifactId>r2dbc-bom</artifactId>
+				<version>${r2dbc.releasetrain}</version>
+				<type>pom</type>
+				<scope>import</scope>
+			</dependency>
 			<dependency>
 				<groupId>org.mockito</groupId>
 				<artifactId>mockito-core</artifactId>
@@ -201,16 +201,6 @@
 				<artifactId>spring-data-commons</artifactId>
 				<version>${springdata-commons.version}</version>
 			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib</artifactId>
-				<version>${kotlin}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-reflect</artifactId>
-				<version>${kotlin}</version>
-			</dependency>
 			<dependency>
 				<groupId>org.testcontainers</groupId>
 				<artifactId>junit-jupiter</artifactId>

spring-data-neo4j/pom.xml

@@ -73,10 +73,8 @@
 		<dependency>
 			<groupId>io.r2dbc</groupId>
 			<artifactId>r2dbc-h2</artifactId>
-			<version>0.8.0.M8</version>
 			<scope>test</scope>
 		</dependency>
-
 		<dependency>
 			<groupId>org.apiguardian</groupId>
 			<artifactId>apiguardian-api</artifactId>
@@ -128,10 +126,12 @@
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
 			<artifactId>kotlin-stdlib</artifactId>
+			<optional>true</optional>
 		</dependency>
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
 			<artifactId>kotlin-reflect</artifactId>
+			<optional>true</optional>
 		</dependency>
 		<dependency>
 			<groupId>org.testcontainers</groupId>