Remove invalid ruby-version-file input from GitHub Actions workflows

[Copilot]

The ruby/setup-ruby@v1.283.0 action was being called with ruby-version-file input, which doesn't exist in this version. The valid input is ruby-version, which automatically reads from .ruby-version when unset.

Changes

• Removed ruby-version-file: '.ruby-version' from deploy.yml and jekyll-build.yml workflows
• Action now auto-detects .ruby-version file at repository root (default behavior)

This eliminates the CI warning while preserving identical Ruby version resolution behavior.

Original prompt

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This section details on the original issue you should resolve

<issue_title>CI: Warning: Unexpected input(s)</issue_title>
<issue_description> Warning: Unexpected input(s) 'ruby-version-file', valid inputs are ['ruby-version', 'rubygems', 'bundler', 'bundler-cache', 'working-directory', 'cache-version', 'self-hosted', 'windows-toolchain', 'token']

https://github.com/jser/jser.github.io/actions/runs/21033296833/job/60474459588?pr=1343</issue_description>

<agent_instructions>fix ci</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes CI: Warning: Unexpected input(s) #1346

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