Bump golang from 85aacbe to dadce81 in /integration (#1243)

Bumps golang from `85aacbe` to `dadce81`.

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

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

integration/Dockerfile

@@ -1,6 +1,6 @@
 # This Dockerfile builds a base image for the certificate-transparency-go CloudBuild integration testing.
 # See https://hub.docker.com/_/golang for the set of golang base images.
-FROM golang:1.21.4-bookworm@sha256:85aacbed94a248f792beb89198649ddbc730649054b397f8d689e9c4c4cceab7 as ct_testbase
+FROM golang:1.21.4-bookworm@sha256:dadce81d7b2517bef188b89d3df3288780f87f24903c2607fb39c93a21d5365c as ct_testbase
 
 WORKDIR /testbase