build(deps): bump swagger-parser.version from 2.0.20 to 2.0.21 (#10)

Bumps `swagger-parser.version` from 2.0.20 to 2.0.21.

Updates `swagger-parser-v3` from 2.0.20 to 2.0.21

Updates `swagger-parser` from 2.0.20 to 2.0.21
- [Release notes](https://github.com/swagger-api/swagger-parser/releases)
- [Commits](swagger-api/swagger-parser@v2.0.20...v2.0.21)

Updates `swagger-parser-v2-converter` from 2.0.20 to 2.0.21

Signed-off-by: dependabot[bot] <support@github.com>

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

Author: dependabot[bot]

pom.xml

@@ -66,7 +66,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <project.scm.id>github</project.scm.id>
 
-        <swagger-parser.version>2.0.20</swagger-parser.version>
+        <swagger-parser.version>2.0.21</swagger-parser.version>
         <slf4j.version>1.7.30</slf4j.version>
     </properties>