Merge pull request #625 from mackerelio/dependabot/docker/golang-1.22…

…-alpine

Bump golang from 1.21-alpine to 1.22-alpine

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21-alpine AS builder
+FROM golang:1.22-alpine AS builder
 RUN apk add --no-cache make git
 WORKDIR /go/src/github.com/mackerelio/mkr/
 COPY . .