Bump golang from 1.25-alpine to 1.26-alpine (#726)

Bumps golang from 1.25-alpine to 1.26-alpine.

---
updated-dependencies:
- dependency-name: golang
  dependency-version: 1.26-alpine
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Dockerfile

@@ -1,7 +1,7 @@
 # Copyright 2022 - offen.software <hioffen@posteo.de>
 # SPDX-License-Identifier: MPL-2.0
 
-FROM golang:1.25-alpine AS builder
+FROM golang:1.26-alpine AS builder
 
 WORKDIR /app
 COPY . .