Bump golang from 114b9cc to 9c7ea4a in /integration (#1166)

Bumps golang from `114b9cc` to `9c7ea4a`.

---
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:1.21.1-bookworm@sha256:114b9cc39f435cfc34e2d48d0cb12cba2015a87f359f5dbf3ee3b6cf3591b7fb as ct_testbase
+FROM golang:1.21.1-bookworm@sha256:9c7ea4a4924ae24913401af45c9b6f439d0f782267584738d1cc1099d8b7a02c as ct_testbase
 
 WORKDIR /testbase