Bump golang from 1.20.6-alpine3.17 to 1.21.3-alpine3.17

Bumps golang from 1.20.6-alpine3.17 to 1.21.3-alpine3.17.

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,5 +1,5 @@
 # Builder image
-FROM golang:1.20.6-alpine3.17 AS builder
+FROM golang:1.21.3-alpine3.17 AS builder
 
 WORKDIR /build