chore(docker): bump golang from 1.25-alpine to 1.26-alpine (#7)

Bumps golang from 1.25-alpine to 1.26-alpine.

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

Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:1.25-alpine AS builder
+FROM golang:1.26-alpine AS builder
 
 RUN apk add --no-cache git ca-certificates