Update nginx Docker tag to v1.29.0

| datasource | package | from   | to     |
| ---------- | ------- | ------ | ------ |
| docker     | nginx   | 1.28.0 | 1.29.0 |


Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build/Dockerfile.nginx

@@ -4,7 +4,7 @@ FROM scratch AS nginx-files
 # the following links can be replaced with local files if needed, i.e. ADD --chown=101:1001 <local_file> <container_file>
 ADD --link --chown=101:1001 https://cs.nginx.com/static/keys/nginx_signing.rsa.pub nginx_signing.rsa.pub
 
-FROM nginx:1.28.0-alpine-otel
+FROM nginx:1.29.0-alpine-otel
 
 # renovate: datasource=github-tags depName=nginx/agent
 ARG NGINX_AGENT_VERSION=v3.0.2