fix: resolve config file path against GITHUB_WORKSPACE

[matmar10]

Summary

• Fixes the config_path input resolving to the action's own dist/ directory instead of the consuming repo's workspace
• Replaces path.join(__dirname, '/../', configPath) with path.join(process.env.GITHUB_WORKSPACE || process.cwd(), configPath)

Closes #26

Root cause

__dirname inside dist/index.js points to the action's install path (e.g. …/_actions/matmar10/prcolinter/v1/dist). Going one level up still lands inside the action bundle, not the checked-out consumer repo. GITHUB_WORKSPACE is the correct root.

Test plan

• Open a PR in a repo that has .github/prcolinterrc.json with at least one rule override and verify the rule takes effect
• Verify the debug log shows the correct resolved path under GITHUB_WORKSPACE
• Verify behaviour is unchanged when no config file is present (file not found → empty {} → only default rules apply)

🤖 Generated with Claude Code

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