title: Unable to upgrade swagger2 version from 2.7.0 to 3.00 in Spring REST API(regular Spring not sprint boot)
body: <p>My project is working fine with swagger2 version 2.7.0.not spring boot(spring mvc only)
  I am going to upgrade it 3.0.0 but it's giving plugin errors.</p>
  <p><code>java.lang.nosuchMethodError:org.springframework.plugin.core.pluginRegistry.getPluginFor(Ljava/lang/Object;)Ljava/util/Optional;</code></p>
  <p>My config as below:</p>
  <pre><code>&lt;dependency&gt;
      &lt;groupId&gt;io.springfox&lt;/groupId&gt;
      &lt;artifactId&gt;springfox-swagger2&lt;/artifactId&gt;
      &lt;version&gt;3.0.0&lt;/version&gt;
  &lt;/dependency&gt;
  
  &lt;dependency&gt;
      &lt;groupId&gt;io.springfox&lt;/groupId&gt;
      &lt;artifactId&gt;springfox-swagger-ui&lt;/artifactId&gt;
      &lt;version&gt;3.0.0&lt;/version&gt;
  &lt;/dependency&gt;
  
  
  Update: As mentioned in https://github.com/springfox/springfox
  Step 2 : Add @EnableOpenApi for open API (and @EnableSwagger2WebMvc or @EnableSwagger2WebFlux for older versions)
  I added @EnableSwagger2WebMvc in class ,Then it's asking dependency of springfox-swagger2,
  as this coming from :
  http://springfox.github.io/springfox/javadoc/snapshot/springfox/documentation/swagger2/annotations/EnableSwagger2WebMvc.html 
  which is part of springfox-swagger2 dependency
  
  Hence I am confused what to do..
  can you please help cleaner approach with steps .
  If I don't  use @EnableSwagger2WebMvc/EnableSwagger2
  Swagger is not getting loaded
  </code></pre>