fix(#2608): auto-detect digger-os and digger-arch inputs in github ac…

[Mallikarjunadevops]

What Resolves #2608.

Currently, action.yml hardcodes its inputs to default to Linux and X64. When users run Digger on non-x86 Linux machines or macOS self-hosted runners (Apple Silicon), the CLI download step fails because it blindly requests the legacy Linux-X64 binary payload without accounting for the actual runner architecture.
This Pull Request introduces auto-detection functionality that gracefully falls back to the native runner.os and runner.arch metrics exclusively when the digger-os or digger-arch inputs are omitted.

How

• Updated action.yml to set the default value of the OS and Architecture inputs to an empty string "".
• Added a bash variable-assignment block inside the name: download, install, and run digger step.
• Mapped GitHub's runner.os (Linux, macOS, Windows) and runner.arch (X64, ARM64, etc.) outputs into their corresponding Golang static binary compilation identifiers (linux, darwin, amd64, arm64, etc.).
• Backwards compatibility is preserved utilizing strict -z empty-string checks; if a user continues explicitly providing properties to the with: segment on old configurations, auto-detection gracefully yields control.

Testing

• Performed static bash syntax validation on the modified shell payload snippet to prevent composite action crashes.

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Disclosure: I consulted with an AI assistant while writing the implementation for this auto-detect feature.
reviewed and verified manually._