Bump nginx from 1.27.3 to 1.27.4 in /.github

Bumps nginx from 1.27.3 to 1.27.4.

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

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

.github/Dockerfile

@@ -1,3 +1,3 @@
 # Dummy Dockerfile for dependabot, if it finds an update we need to update docker-compose.yml
 #
-FROM nginx:1.27.3
+FROM nginx:1.27.4