Maintenance: update PR template to include `closes #` after Issue Number

[dreamorosi]

Summary

Improve our Pull Request template to encourage explicit issue linking by adding the closes #<issue-number> keyword right after the Issue Number: field.

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Why is this needed?

• Automatic linking & closure: When contributors include closes #123, GitHub will automatically link and close that issue upon merge.

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Solution

In the existing .github/PULL_REQUEST_TEMPLATE.md, locate the line:

**Issue Number:**

and update it to:

**Issue Number:** (add `closes #<issue-number>` immediately after)

For example:

**Issue Number:** closes #123

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Acknowledgment

• This request meets Lambda Powertools Tenets
• Should this apply to other Powertools languages? (e.g., TypeScript, Java, .NET)

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Please react with 👍 and share your use case to help us prioritize this update.

[powertools-for-aws-oss-automation]

Warning

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[github-actions]

This is now released under 3.20.0 version!