Update readme and dockerfile

[thelovekesh]

• Add command in readme for installation using go.
• Update dockerfile to have binary target to keep build clean.

[github-actions]

📦 wpm cli builds 📦

• darwin/amd64 - build
• darwin/arm64 - build
• linux/amd64 - build
• linux/arm/v6 - build
• linux/arm/v7 - build
• linux/arm64 - build
• linux/ppc64le - build
• linux/riscv64 - build
• linux/s390x - build
• windows/amd64 - build
• windows/arm64 - build

[gemini-code-assist]

Code Review

This pull request introduces a new image stage in the Dockerfile, adds Go installation instructions to the README, and updates the Docker Bake configuration. Feedback suggests using a more standard PATH or binary location in the Dockerfile, adding language tags to README code blocks for better syntax highlighting, and maintaining consistent attribute ordering (placing inherits at the top) in the docker-bake.hcl file.