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.

---

Why is this needed?

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

---

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

---

Acknowledgment

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

---

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

[powertools-for-aws-oss-automation]

Warning

This issue is now closed. Please be mindful that future comments are hard for our team to see.
If you need more assistance, please either reopen the issue, or open a new issue referencing this one.
If you wish to keep having a conversation with other community members under this issue feel free to do so.