build(deps): bump golang from 1.22 to 1.23 in /docker/test-http

Bumps golang from 1.22 to 1.23.

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

Signed-off-by: dependabot[bot] <[email protected]>

docker/test-http/Dockerfile

@@ -1,7 +1,7 @@
 # The `test-http` image gets built by `pkg/kubeapply` for use by
 # various kubeapply-templated YAML files.
 
-FROM golang:1.22
+FROM golang:1.23
 COPY httptest.go /usr/local/bin/httptest.go
 RUN go build -o /usr/local/bin/httptest /usr/local/bin/httptest.go
 ENTRYPOINT ["/usr/local/bin/httptest"]