Bump golang from 1.22-alpine to 1.23-alpine

Bumps golang from 1.22-alpine to 1.23-alpine.

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.22-alpine AS builder
+FROM golang:1.23-alpine AS builder
 RUN apk add --no-cache make git
 WORKDIR /go/src/github.com/mackerelio/mkr/
 COPY . .