Bump github.com/safing/spn from 0.4.14 to 0.4.15

Bumps [github.com/safing/spn](https://github.com/safing/spn) from 0.4.14 to 0.4.15.
- [Release notes](https://github.com/safing/spn/releases)
- [Commits](https://github.com/safing/spn/compare/v0.4.14...v0.4.15)

---
updated-dependencies:
- dependency-name: github.com/safing/spn
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/miekg/dns v1.1.50
 	github.com/oschwald/maxminddb-golang v1.9.0
 	github.com/safing/portbase v0.15.0
-	github.com/safing/spn v0.4.14
+	github.com/safing/spn v0.4.15
 	github.com/shirou/gopsutil v3.21.11+incompatible
 	github.com/spf13/cobra v1.5.0
 	github.com/stretchr/testify v1.8.0