This PR adds a section to the libpostal README linking to the community-maintained multi-architecture Docker image.

[mml555]

This PR adds a section to the libpostal README linking to the community-maintained multi-architecture Docker image.

What this adds

A "Docker" section in the README pointing users to mml555/libpostal-docker, which provides:

• Multi-architecture support: linux/amd64 and linux/arm64 (Apple Silicon, AWS Graviton, Oracle Ampere)
• HTTP API: Simple REST endpoints for parsing and normalization
• Pre-built images: Available on both GitHub Container Registry and Docker Hub
• Automated builds: GitHub Actions CI/CD for continuous updates

Why this is useful

1. Solves ARM64 issues - Several issues mention ARM64 build problems (Latest master not building on arm64 - segfault #690, Build error 123 while building docker image #593). This image handles architecture detection and disables SSE2 automatically on ARM.

2. Reduces setup friction - No need to compile from source or download 2GB of data manually. Just docker run.

3. Production-ready - Includes health checks, graceful shutdown, and Gunicorn for production use.

Proposed README addition

## Docker

A community-maintained multi-architecture Docker image is available:

\`\`\`bash
# GitHub Container Registry
docker run -d -p 4400:4400 ghcr.io/mml555/libpostal-docker:latest

# Docker Hub
docker run -d -p 4400:4400 mml555/libpostal:latest
\`\`\`

This provides HTTP endpoints for parsing (`/parser`) and normalization (`/expand`).
See [mml555/libpostal-docker](https://github.com/mml555/libpostal-docker) for full documentation.

Related Issues

• Latest master not building on arm64 - segfault #690 - Latest master not building on arm64 - segfault
• Build error 123 while building docker image #593 - Build error 123 while building docker image