upgrade to 2.0.9 and update README.md

Author: stevehu

README.md

@@ -79,7 +79,7 @@ Include the dependency in the project pom:
   <dependency>
     <groupId>com.mservicetech</groupId>
     <artifactId>openapi-schema-validation</artifactId>
-    <version>2.0.0</version>
+    <version>2.0.9</version>
   </dependency>
    ```
 

pom.xml

@@ -19,7 +19,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.mservicetech</groupId>
     <artifactId>openapi-schema-validation</artifactId>
-    <version>2.0.8</version>
+    <version>2.0.9</version>
     <packaging>jar</packaging>
     <description>openapi schema  for openpai 3.*</description>
     <url>https://github.com/mservicetech/openapi-schema-validation</url>