fixes OAS 3.1 dereferencing

Author: frantuma

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/reference/DereferencerContext.java

@@ -20,6 +20,7 @@ public class DereferencerContext {
     protected SwaggerParseResult swaggerParseResult;
     protected boolean addParametersToEachOperation = true;
     protected String currentUri;
+    protected Map<String, String> idsCache = new LinkedHashMap<>();
 
     private Map<String, Reference> referenceSet = new LinkedHashMap<>();
 
@@ -115,6 +116,19 @@ public DereferencerContext referenceSet(Map<String, Reference> referenceSet) {
         return this;
     }
 
+    public Map<String, String> getIdsCache() {
+        return idsCache;
+    }
+
+    public void setIdsCache(Map<String, String> idsCache) {
+        this.idsCache = idsCache;
+    }
+
+    public DereferencerContext idsCache(Map<String, String> idsCache) {
+        this.idsCache = idsCache;
+        return this;
+    }
+
     public DereferencerContext rootUri(String rootUri) {
         this.rootUri = rootUri;
         return this;