Create PULL_REQUEST_TEMPLATE.md

[goodylili]

Description

This PR introduces a standardized pull request template for the NEAR project. The template is designed to enhance the clarity, consistency, and thoroughness of contributions made to the repository.

• What does this PR do?
  This PR adds a Markdown-based pull request template to the repository to ensure contributors provide all necessary details when submitting changes.

• Why are these changes necessary?
  A well-defined template helps maintainers review pull requests efficiently, ensures all contributors follow best practices, and reduces the likelihood of missing key information.

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Checklist

Please ensure the following are completed before submitting your pull request:

• I have reviewed the NEAR contribution guidelines.
• I followed the standard fork-branch-commit workflow.
• I ran all applicable tests locally using yarn test (or equivalent).
• I have checked for broken links by running yarn full-test in the /website directory.
• I included unit tests for any new functionality, where applicable.
• I have verified that my changes pass the CI checks.
• I included steps to reproduce any bugs or issues this PR addresses, if applicable.
• I provided detailed information on environment versions (e.g., node --version, rustc --version).

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Changes Made

• Added: A new pull request template in .github/PULL_REQUEST_TEMPLATE.md.

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Testing

Detail any tests performed to verify functionality:

1. Tested the appearance and usability of the pull request template in a sample repository.
2. Ensured all Markdown syntax renders correctly on GitHub.
3. Simulated creating a pull request using the template to confirm it provides clear guidance.

[goodylili]

Hi @bucanero @gagdiez