Bump credentials from 2.1.18 to 2.6.1.1

Bumps [credentials](https://github.com/jenkinsci/credentials-plugin) from 2.1.18 to 2.6.1.1.
- [Release notes](https://github.com/jenkinsci/credentials-plugin/releases)
- [Changelog](https://github.com/jenkinsci/credentials-plugin/blob/master/CHANGELOG.md)
- [Commits](jenkinsci/credentials-plugin@credentials-2.1.18...credentials-2.6.1.1)

---
updated-dependencies:
- dependency-name: org.jenkins-ci.plugins:credentials
  dependency-type: direct:development
...

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

pom.xml

@@ -168,7 +168,7 @@
     <dependency>
       <groupId>org.jenkins-ci.plugins</groupId>
       <artifactId>credentials</artifactId>
-      <version>2.1.18</version>
+      <version>2.6.1.1</version>
       <scope>test</scope>
     </dependency>
     <dependency>