Bump io.swagger.core.v3:swagger-models from 2.2.20 to 2.2.21 (#717)

Bumps io.swagger.core.v3:swagger-models from 2.2.20 to 2.2.21.

---
updated-dependencies:
- dependency-name: io.swagger.core.v3:swagger-models
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

maven-plugin/build.gradle

@@ -14,7 +14,7 @@ dependencies {
 
     implementation project(':openapi-style-validator-lib')
     implementation 'io.swagger.parser.v3:swagger-parser:2.1.19'
-    implementation 'io.swagger.core.v3:swagger-models:2.2.20'
+    implementation 'io.swagger.core.v3:swagger-models:2.2.21'
     implementation 'org.openapitools.empoa:empoa-swagger-core:2.1.0'
 
     implementation 'org.apache.maven:maven-plugin-api:3.9.6'