Bump golang in /examples/deployment/docker/log_signer (#3528)

Bumps golang from 1.22.3-bookworm to 1.22.4-bookworm.

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

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

examples/deployment/docker/log_signer/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.22.3-bookworm@sha256:5c56bd47228dd572d8a82971cf1f946cd8bb1862a8ec6dc9f3d387cc94136976 as build
+FROM golang:1.22.4-bookworm@sha256:aec47843e52fee4436bdd3ce931417fa980e9055658b5142140925eea3044bea as build
 
 WORKDIR /trillian