Polishing.

Fix JavaDoc and reference doc versions and links.

See gh-198.

pom.xml

@@ -303,8 +303,9 @@
 						<links>
 							<link>https://docs.spring.io/spring-data/commons/docs/current/api</link>
 							<link>https://docs.spring.io/spring-data/keyvalue/docs/current/api</link>
-							<link>http://docs.spring.io/spring/docs/current/javadoc-api</link>
-							<link>http://docs.oracle.com/javase/8/docs/api</link>
+							<link>https://docs.spring.io/spring/docs/current/javadoc-api</link>
+							<link>https://docs.spring.io/spring-security/site/docs/current/api</link>
+							<link>https://docs.oracle.com/javase/8/docs/api</link>
 						</links>
 					</configuration>
 				</plugin>

src/main/asciidoc/index.adoc

@@ -7,7 +7,7 @@ Mark Paluch;
 :spring-framework-docs: https://docs.spring.io/spring/docs/{springVersion}/spring-framework-reference/
 :self-docs-root: https://docs.spring.io/spring-vault/docs/{version}/
 
-(C) 2016-2017 The original authors.
+(C) 2016-2018 The original authors.
 
 NOTE: _Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically._
 

src/main/asciidoc/preface.adoc

@@ -52,7 +52,7 @@ for external services such as MySQL, PostgreSQL, Apache Cassandra, Consul, AWS a
 [[requirements]]
 == Requirements
 
-Spring Vault 1.x binaries requires JDK level 8.0 and above, and http://spring.io/docs[Spring Framework] {springVersion} and above.
+Spring Vault 2.x binaries requires JDK level 8.0 and above, and http://spring.io/docs[Spring Framework] {springVersion} and above.
 
 In terms of Vault, https://www.vaultproject.io/[Vault] at least 0.5.