Update README.md (clarify installation go toolchain requirements)

[MenyMarquez1978]

Summary

• Add a short note after the Installation snippet recommending a recent Go version and reminding users to have GOBIN on PATH

Rationale

• Helps new users understand the Go toolchain expectations and avoids confusion when the withdrawer binary is not immediately available after go install

[cb-heimdall]

🟡 Heimdall Review Status

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Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1