build(deps): bump github.com/sumup/sumup-go

Bumps the sumup-sdk group in /backend/go with 1 update: [github.com/sumup/sumup-go](https://github.com/sumup/sumup-go).


Updates `github.com/sumup/sumup-go` from 0.12.0 to 0.13.0
- [Release notes](https://github.com/sumup/sumup-go/releases)
- [Changelog](https://github.com/sumup/sumup-go/blob/main/CHANGELOG.md)
- [Commits](sumup/sumup-go@v0.12.0...v0.13.0)

---
updated-dependencies:
- dependency-name: github.com/sumup/sumup-go
  dependency-version: 0.13.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: sumup-sdk
...

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

Author: dependabot[bot]

backend/go/go.mod

@@ -4,6 +4,6 @@ go 1.23.0
 
 toolchain go1.23.2
 
-require github.com/sumup/sumup-go v0.12.0
+require github.com/sumup/sumup-go v0.13.0
 
 require golang.org/x/oauth2 v0.27.0 // indirect

backend/go/go.sum

@@ -1,6 +1,6 @@
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/sumup/sumup-go v0.12.0 h1:sUBYRzRNlSArvayKMV9Rplb+Vc7+PHQ0osaSqo22cDg=
-github.com/sumup/sumup-go v0.12.0/go.mod h1:UgT9aaxvUBrAiRpunqyb1zi5v/+1z+6Lr6p6bgL8EYI=
+github.com/sumup/sumup-go v0.13.0 h1:35Xpv8cNLS5O02voKgwgks8Gz2QU53Ek8emlOyVuvkU=
+github.com/sumup/sumup-go v0.13.0/go.mod h1:UgT9aaxvUBrAiRpunqyb1zi5v/+1z+6Lr6p6bgL8EYI=
 golang.org/x/oauth2 v0.27.0 h1:da9Vo7/tDv5RH/7nZDz1eMGS/q1Vv1N/7FCrBhI9I3M=
 golang.org/x/oauth2 v0.27.0/go.mod h1:onh5ek6nERTohokkhCD/y2cV4Do3fxFHFuAejCkRWT8=