NumPy 1.17.2 release

1. 1856aca Add links for GitHub Sponsors button. by Ralf Gommers · 6 years ago
2. 6e22ada Update links in PULL_REQUEST_TEMPLATE.md by Bharat Raghunathan · 6 years ago
3. 6ab8b85 DOC: add a Code of Conduct document. by Ralf Gommers · 7 years ago
4. a193dcd Make fixes requested by @rgommers by Eric Wieser · 7 years ago
5. 471ada7 fixes from review by mattip · 7 years ago
6. 9f227da reformat as html comments by mattip · 7 years ago
7. d7c9924 DOC: add templates for issues and PR by mattip · 7 years ago