Add a bug issue template

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,31 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ""
+labels: ""
+assignees: ""
+---
+
+**Is this a bug with the Elm package wolfadex/elm-open-api, or the CLI tool elm-open-api?**
+These are 2 related but separate tools. This is the Elm package wolfadex/elm-open-api, used
+for decoding the Open API spec into Elm types for convenient use in other places. There's
+also the related CLI tool [elm-open-api](https://github.com/wolfadex/elm-open-api-cli) by
+@wolfadex, which uses this package to generate Elm SDKS.
+
+If this is a bug with the Elm package, you're in the right place! If this is a bug with the
+CLI tool, please [report that issue here]().
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Additional context**
+Add any other context about the problem here.