build(deps): bump github.com/go-git/go-billy/v5 in /tests/integration

Bumps [github.com/go-git/go-billy/v5](https://github.com/go-git/go-billy) from 5.8.0 to 5.9.0.
- [Release notes](https://github.com/go-git/go-billy/releases)
- [Commits](https://github.com/go-git/go-billy/compare/v5.8.0...v5.9.0)

---
updated-dependencies:
- dependency-name: github.com/go-git/go-billy/v5
  dependency-version: 5.9.0
  dependency-type: indirect
...

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

tests/integration/go.mod

@@ -62,7 +62,7 @@ require (
 	github.com/fluxcd/pkg/version v0.14.0 // indirect
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
 	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
-	github.com/go-git/go-billy/v5 v5.8.0 // indirect
+	github.com/go-git/go-billy/v5 v5.9.0 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-openapi/jsonpointer v0.21.1 // indirect