chore(deps): update nginxinc/nginx-unprivileged docker tag to v1.29 (#426)

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

Author: renovate[bot]

Dockerfile

@@ -24,7 +24,7 @@ RUN wkhtmltopdf --enable-internal-links --enable-local-file-access \
     --dpi 600 \
     /pdf/index.html /pdf.pdf
 
-FROM nginxinc/nginx-unprivileged:1.28-alpine
+FROM nginxinc/nginx-unprivileged:1.29-alpine
 
 LABEL maintainer acend.ch
 LABEL org.opencontainers.image.title "acend.ch's Container Basics Training"