Fix ruby dependencies for docs

spring-cloud-build/pom.xml

@@ -280,6 +280,7 @@ limitations under the License.
 						<plugin>
 							<groupId>org.asciidoctor</groupId>
 							<artifactId>asciidoctor-maven-plugin</artifactId>
+                            <version>1.5.2</version>
 							<executions>
 								<execution>
 									<id>generate-docs</id>
@@ -327,8 +328,13 @@ limitations under the License.
 								<dependency>
 									<groupId>org.jruby</groupId>
 									<artifactId>jruby-complete</artifactId>
-									<version>1.7.12</version>
+									<version>1.7.17</version>
 								</dependency>
+                                <dependency>
+                                  <groupId>org.asciidoctor</groupId>
+                                  <artifactId>asciidoctorj</artifactId>
+                                  <version>1.5.2</version>
+                                </dependency>
 							</dependencies>
 							<executions>
 								<execution>