templates/release: minor updates

Link to GitHub release creation form and openslide-winbuild release
template.

Author: bgilbert

.github/ISSUE_TEMPLATE/release.md

@@ -4,7 +4,7 @@
 - [ ] Update `CHANGELOG.txt` and version in `configure.ac`
 - [ ] Create and push signed tag
 - [ ] `git clean -dxf && autoreconf -i && ./configure && make distcheck`
-- [ ] Attach release notes to [GitHub release](https://github.com/openslide/openslide-java/releases), set pre-release flag, and upload tarballs
-- [ ] Update openslide-winbuild
+- [ ] Attach release notes to [GitHub release](https://github.com/openslide/openslide-java/releases/new), set pre-release flag, and upload tarballs
+- [ ] [Update openslide-winbuild](https://github.com/openslide/openslide-winbuild/issues/new?labels=release&template=release.md)
 - [ ] Update website: `_data/releases.yaml`, `_includes/news.markdown`
 - [ ] Send mail to -announce and -users