chore: bump golang from d9f7519 to 851af0a in /build/tooling

Bumps golang from `d9f7519` to `851af0a`.

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

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

build/tooling/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.20-bullseye@sha256:d9f75197f484a4d7e008a0a8f7d1e68344ea1c1ba030273d5ab1567e129eed55
+FROM golang:1.20-bullseye@sha256:851af0a8ca4eba552c84db5b2edac7f3be15deb5892217961a1d4b175585a603
 
 RUN GO111MODULE=on go install sigs.k8s.io/controller-tools/cmd/controller-gen@v0.9.0
 RUN GO111MODULE=on go install k8s.io/code-generator/cmd/conversion-gen@v0.25.4