Update changelog for v1.7.13

[juarezr]

This PR has the objective of preparing a new release.

Changes

1. Updated changelog for v1.7.13
2. Fixed pull request template spelling

Checklist

Use this checklist to ensure the quality of pull requests that include new code and/or make changes to existing code.

• [ ] Source Code rules apply:
  • [ ] Includes unit tests
  • [ ] New functions have docstrings with examples that can be run with doctest
  • [ ] New functions are included in API docs
  • [ ] Docstrings include notes for any changes to API or behavior
  • [ ] All changes are documented in docs/changes.rst
• [ ] Versioning and history tracking rules apply:
  • [ ] Using atomic commits when possible
  • [ ] Commits are reversible when possible
  • [ ] There are no incomplete changes in the pull request
  • [ ] There is no accidental garbage added to the source code
• [ ] Testing rules apply:
  • [ ] Tested locally using tox / pytest
  • [ ] Automated testing passes (see CI)
  • [ ] Unit test coverage has not decreased (see Coveralls)
• [X] State of these changes is:
  • [ ] Just a proof of concept
  • [ ] Work in progress / Further changes needed
  • [X] Ready to review
  • [X] Ready to merge

[coveralls]

Pull Request Test Coverage Report for Build 3534538103

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 91.116%

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Totals
Change from base Build 3532338572:	0.0%
Covered Lines:	12758
Relevant Lines:	14002

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💛 - Coveralls