Added bug fix PR template

Author: kbgg

.github/PULL_REQUEST_TEMPLATE/bug_fix_template.md

@@ -0,0 +1,11 @@
+Related Issue(s): #
+
+Description:
+
+Example File URL to be used to validate fix: `https://foo.bar`
+
+PR Checklist:
+
+- [ ] This PR is made against the dev branch (all proposed changes except releases should be against dev, not main).
+- [ ] I have followed the steps to reproduce in the related issue(s) and the issues have been validated as fixed.
+- [ ] I have added my changes to the [CHANGELOG](https://github.com/source-cooperative/viewers/blob/dev/CHANGELOG.md).