Bump no.nav.security:mock-oauth2-server in the gradle group (#279)

Bumps the gradle group with 1 update: [no.nav.security:mock-oauth2-server](https://github.com/navikt/mock-oauth2-server).


Updates `no.nav.security:mock-oauth2-server` from 2.1.4 to 2.1.5
- [Release notes](https://github.com/navikt/mock-oauth2-server/releases)
- [Commits](navikt/mock-oauth2-server@2.1.4...2.1.5)

---
updated-dependencies:
- dependency-name: no.nav.security:mock-oauth2-server
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: gradle
...

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

build.gradle.kts

@@ -8,7 +8,7 @@ val imageIOVersion = "3.10.1"
 val jsonassertVersion = "1.5.1"
 val fuelVersion = "2.3.1"
 val tokenSupportVersion = "4.1.4"
-val mockOauth2ServerVersion = "2.1.4"
+val mockOauth2ServerVersion = "2.1.5"
 
 val mainClass = "no.nav.helse.K9JoarkKt"