Bump io.ktor:ktor-server-default-headers from 2.3.7 to 2.3.9 (#601)

Bumps [io.ktor:ktor-server-default-headers](https://github.com/ktorio/ktor) from 2.3.7 to 2.3.9.
- [Release notes](https://github.com/ktorio/ktor/releases)
- [Changelog](https://github.com/ktorio/ktor/blob/2.3.9/CHANGELOG.md)
- [Commits](ktorio/ktor@2.3.7...2.3.9)

---
updated-dependencies:
- dependency-name: io.ktor:ktor-server-default-headers
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle.kts

@@ -44,7 +44,7 @@ dependencies {
     ////////////////////
     api("io.ktor:ktor-server-jetty:2.3.7")
     api("io.ktor:ktor-server-websockets:2.3.0")
-    api("io.ktor:ktor-server-default-headers:2.3.7")
+    api("io.ktor:ktor-server-default-headers:2.3.9")
     api("io.ktor:ktor-server-compression:2.3.9")
     api("io.ktor:ktor-server-caching-headers:2.3.9")
     api("io.ktor:ktor-network-tls-certificates:2.3.9")