deps: update dependency go to v1.25.6 (#1312)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [go](https://redirect.github.com/golang/go) | | patch | `1.25.5` →
`1.25.6` |
| [go](https://go.dev/)
([source](https://redirect.github.com/golang/go)) | toolchain | patch |
`1.25.5` → `1.25.6` |

---

### Release Notes

<details>
<summary>golang/go (go)</summary>

###
[`v1.25.6`](https://redirect.github.com/golang/go/compare/go1.25.5...go1.25.6)

[Compare
Source](https://redirect.github.com/golang/go/compare/go1.25.5...go1.25.6)

</details>

---

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go.mod

@@ -2,7 +2,7 @@ module github.com/hetznercloud/cli
 
 go 1.24.0
 
-toolchain go1.25.5
+toolchain go1.25.6
 
 require (
 	github.com/BurntSushi/toml v1.6.0

mise.toml

@@ -1,5 +1,5 @@
 [tools]
-go = "1.25.5"
+go = "1.25.6"
 "go:go.uber.org/mock/mockgen" = "v0.6.0"
 "github:golangci/golangci-lint" = "2.8.0"    # renovate: datasource=github-releases depName=golangci/golangci-lint
 "github:goreleaser/goreleaser" = "v2.13.3"   # renovate: datasource=github-releases depName=goreleaser/goreleaser