Bump org.assertj:assertj-core in the dev-deps group (#353)

Bumps the dev-deps group with 1 update: [org.assertj:assertj-core](https://github.com/assertj/assertj).


Updates `org.assertj:assertj-core` from 3.25.3 to 3.26.0
- [Release notes](https://github.com/assertj/assertj/releases)
- [Commits](assertj/assertj@assertj-build-3.25.3...assertj-build-3.26.0)

---
updated-dependencies:
- dependency-name: org.assertj:assertj-core
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dev-deps
...

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

pom.xml

@@ -46,7 +46,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <fpsak.nare.version>2.6.1</fpsak.nare.version>
         <jupiter.version>5.10.2</jupiter.version>
-        <assertj.version>3.25.3</assertj.version>
+        <assertj.version>3.26.0</assertj.version>
 
         <!-- Sonar felles -->
         <sonar.organization>navikt</sonar.organization>