chore(deps): update golang Docker tag to v1.21.2 (#50)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Dockerfile

@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
 ## Build stage
-FROM golang:1.21.1-alpine as build
+FROM golang:1.21.2-alpine as build
 
 RUN apk --no-cache add ca-certificates tzdata
 RUN addgroup --gid 65532 kani && \