Build against Social snapshots for better compatibility

The latest snapshots for Spring Social, Spring Social Facebook, and
Spring Social Twitter improve the compatibility with each other,
Spring Framework 5 and Thymeleaf 3.

See gh-6258

spring-boot-dependencies/pom.xml

@@ -170,10 +170,10 @@
 		<spring-security-jwt.version>1.0.7.RELEASE</spring-security-jwt.version>
 		<spring-security-oauth.version>2.0.12.RELEASE</spring-security-oauth.version>
 		<spring-session.version>2.0.0.BUILD-SNAPSHOT</spring-session.version>
-		<spring-social.version>2.0.0.M2</spring-social.version>
-		<spring-social-facebook.version>3.0.0.M1</spring-social-facebook.version>
+		<spring-social.version>2.0.0.BUILD-SNAPSHOT</spring-social.version>
+		<spring-social-facebook.version>3.0.0.BUILD-SNAPSHOT</spring-social-facebook.version>
 		<spring-social-linkedin.version>2.0.0.M1</spring-social-linkedin.version>
-		<spring-social-twitter.version>2.0.0.M1</spring-social-twitter.version>
+		<spring-social-twitter.version>2.0.0.BUILD-SNAPSHOT</spring-social-twitter.version>
 		<spring-ws.version>2.4.0.RELEASE</spring-ws.version>
 		<sqlite-jdbc.version>3.15.1</sqlite-jdbc.version>
 		<statsd-client.version>3.1.0</statsd-client.version>