Modified the PR template to include README.md update reqirement if ne…

[bgorski]

…cessary

Description (*)

With the introduction of the README.md template, there is a requirement of describing module installation, structure and extension points in the readme.
We need to pay special attention to README.md always being up to date, because an outdated readme can do more harm than good. This is why all code contributors need to be aware that they are supposed to modify README.md as well when they create modifications that affect any of readme predefined sections.

Related Pull Requests

Fixed Issues (if relevant)

1. Fixes magento/catalog-storefront#<issue_number>

Questions or comments

Code Review Checklist (*)

See detailed checklist

• Story AC is completed
• proposed changes correspond to Magento Technical Vision
• new or changed code is covered with web-api/integration tests (if applicable)
  • expected results in test verified with data from fixture
• no backward incompatible changes
• Export API (et_schema.xml) and SF API schemas (proto schema) are reflected in the codebase
  • prerequisite: story branch created with all needed generated classes according to proposes schema-changes
  • DTO classes do not contain any manual changes (Magento\CatalogExportApi*, Magento\CatalogStorefrontApi*)
• Class usage: magento/catalog-storefront repo don't use directly classes from magento/saas-export repo and vise-verse
  • Check composer.json dependencies
• Legacy code is deleted
  • Any Data Providers present in Connector part (Magento\CatalogStorefrontConnector, Magento*Extractor modules)
  • And Data Providers from Export API (magento/saas-export repo) that is not relevant anymore
  • Any DTO for Export API/SF API which does not reflect current schema: et_schema, proto schema
  • Any “mapper” on Message Broker (between Export API and SF API)
    • if mapper still needed, verify fields used in mapping, remove not relevant fields