Merging to release-5.3.9: [TT-13742] update swagger version (#6802)

[TT-13742] update swagger version (#6802)

### **User description**
<details open>
<summary><a href="https://tyktech.atlassian.net/browse/TT-13742"
title="TT-13742" target="_blank">TT-13742</a></summary>
  <br />
  <table>
    <tr>
      <th>Summary</th>
      <td>Update Tyk API documentation for 5.3.9/5.7.1 release</td>
    </tr>
    <tr>
      <th>Type</th>
      <td>
<img alt="Task"
src="https://tyktech.atlassian.net/rest/api/2/universal_avatar/view/type/issuetype/avatar/10318?size=medium"
/>
        Task
      </td>
    </tr>
    <tr>
      <th>Status</th>
      <td>In Dev</td>
    </tr>
    <tr>
      <th>Points</th>
      <td>N/A</td>
    </tr>
    <tr>
      <th>Labels</th>
      <td>-</td>
    </tr>
  </table>
</details>
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https://tyktech.atlassian.net/browse/TT-13742 updates swagger version


___

### **PR Type**
documentation


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### **Description**
- Updated the OpenAPI specification in `swagger.yml` to reflect the new
version `5.3.9`.
- This change ensures the API documentation aligns with the latest
release version.



___



### **Changes walkthrough** 📝
<table><thead><tr><th></th><th align="left">Relevant
files</th></tr></thead><tbody><tr><td><strong>Documentation</strong></td><td><table>
<tr>
  <td>
    <details>
<summary><strong>swagger.yml</strong><dd><code>Update OpenAPI version in
`swagger.yml` to 5.3.9</code>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; </dd></summary>
<hr>

swagger.yml

<li>Updated the <code>version</code> field in the OpenAPI specification
from <code>5.3.8</code> to <br><code>5.3.9</code>.<br> <li> No other
changes were made to the file.<br>


</details>


  </td>
<td><a
href="https://github.com/TykTechnologies/tyk/pull/6802/files#diff-8f3c4cb253eee09ae2401daa7279a8bbfbfd4168bb579c3ac0ee5c672d63bb2c">+1/-1</a>&nbsp;
&nbsp; &nbsp; </td>

</tr>
</table></td></tr></tr></tbody></table>

___

> 💡 **PR-Agent usage**: Comment `/help "your question"` on any pull
request to receive relevant information

swagger.yml

@@ -1,7 +1,7 @@
 openapi: 3.0.0
 info:
   title: Tyk Gateway API
-  version: 5.3.8
+  version: 5.3.9
   description: |-
     The Tyk Gateway API is the primary means for integrating your application with the Tyk API Gateway system. This API is very small, and has no granular permissions system. It is intended to be used purely for internal automation and integration.