Bump swagger_version from 1.6.14 to 1.6.15

Bumps `swagger_version` from 1.6.14 to 1.6.15.

Updates `io.swagger:swagger-annotations` from 1.6.14 to 1.6.15

Updates `io.swagger:swagger-jaxrs` from 1.6.14 to 1.6.15

---
updated-dependencies:
- dependency-name: io.swagger:swagger-annotations
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: io.swagger:swagger-jaxrs
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

dubbo-extensions-dependencies-bom/pom.xml

@@ -136,7 +136,7 @@
         <rs_api_version>2.1.1</rs_api_version>
         <resteasy_version>3.15.6.Final</resteasy_version>
         <codehaus-jackson_version>1.9.13</codehaus-jackson_version>
-        <swagger_version>1.6.14</swagger_version>
+        <swagger_version>1.6.15</swagger_version>
         <polaris_adapter_version>0.2.1</polaris_adapter_version>
         <maven_flatten_version>1.2.5</maven_flatten_version>
         <byte-buddy.version>1.15.11</byte-buddy.version>