Update docker.io/nginxinc/nginx-unprivileged Docker tag to v1.29 (#351)

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

Author: renovate[bot]

Dockerfile

@@ -24,7 +24,7 @@ RUN wkhtmltopdf --outline-depth 4 \
     --enable-internal-links --enable-local-file-access \
     /pdf/index.html /pdf.pdf
 
-FROM docker.io/nginxinc/nginx-unprivileged:1.28-alpine
+FROM docker.io/nginxinc/nginx-unprivileged:1.29-alpine
 USER root
 COPY nginx.conf /etc/nginx/nginx.conf
 USER 101