feat(deps): bump golang from 1.19-alpine3.18 to 1.21-alpine3.18 (#83)

Bumps golang from 1.19-alpine3.18 to 1.21-alpine3.18.

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

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

Dockerfile

@@ -1,6 +1,6 @@
 # Copyright 2020 Adevinta
 
-FROM golang:1.19-alpine3.18 as builder
+FROM golang:1.21-alpine3.18 as builder
 
 WORKDIR /app