Upgrade swagger-annotations 1.6.12 -> 1.6.13 (#997)

See:
- https://github.com/swagger-api/swagger-core/releases/tag/v1.6.13
- swagger-api/swagger-core@v1.6.12...v1.6.13

pom.xml

@@ -354,7 +354,7 @@
             <dependency>
                 <groupId>io.swagger</groupId>
                 <artifactId>swagger-annotations</artifactId>
-                <version>1.6.12</version>
+                <version>1.6.13</version>
             </dependency>
             <dependency>
                 <groupId>io.swagger.core.v3</groupId>