Adds a workflow that triggers on v* tag pushes and:
- Logs into Docker Hub using DOCKERHUB_USERNAME + DOCKERHUB_TOKEN secrets
- Builds the image from the existing Dockerfile
- Tags it with both the version (e.g. 0.1.4) and 'latest'
- Pushes both tags
GitHub Actions cache is used for layers to speed up subsequent builds.
The current ubuntu-latest Linux release can require a newer glibc than common LTS servers provide. Pinning the x86_64 Linux release job to Ubuntu 22.04 keeps the prebuilt binary compatible with glibc 2.35+ environments while leaving macOS and Windows release jobs unchanged.
Also document the Linux LTS compatibility target in the install section so users understand why the release runner is pinned.
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