🚀 [Feature]: Release-triggering file patterns now configurable (#19)

Repositories can now configure which file changes trigger build, test, and publish stages. Previously, only changes to src/ and README.md were recognized as significant — this was hardcoded and could not be overridden. Repositories that ship additional important files (e.g., examples/, custom config) can now declare their own patterns through the settings file or the action input.

• Fixes PSModule/Process-PSModule#278

New: Configurable important file patterns

The ImportantFilePatterns setting accepts an array of regex patterns. When a PR changes only files that don't match any pattern, build/test/publish stages are skipped.

Via settings file (.github/PSModule.yml):

ImportantFilePatterns:
  - '^src/'
  - '^README\.md$'
  - '^examples/'

Via action input (newline-separated):

- uses: PSModule/Get-PSModuleSettings@v1
  with:
    ImportantFilePatterns: |
      ^src/
      ^README\.md$
      ^examples/

The setting fully replaces the defaults when configured. Include the default patterns in your list if you still want them.

Resolution order: settings file → action input → hardcoded fallback (^src/, ^README\.md$).

Changed: PR skip comment now reflects configured patterns

The PR comment posted when no important files changed now dynamically lists the actual patterns in effect, rather than a hardcoded table.

Technical Details

• action.yml: Added ImportantFilePatterns input with newline-separated default and corresponding PSMODULE_GET_SETTINGS_INPUT_ImportantFilePatterns env var.
• Settings.schema.json: Added top-level ImportantFilePatterns property as array of strings.
• main.ps1: Added resolution logic (settings file → parsed input → hardcoded default). Replaced hardcoded $importantPatterns array with $settings.ImportantFilePatterns. Refactored PR comment to generate the pattern table dynamically.
• README.md: Documented the new input and settings file property with examples.