.github: add issue/PR templates [skip travis]

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,27 @@
+---
+name: Bug report
+about: Create a report if something doesn't work quite right.
+title: ''
+labels: bug
+assignees: ''
+---
+
+<!-- Please do not post usage questions here. Ask them on the PyPSA mailing list: https://groups.google.com/forum/#!forum/pypsa -->
+
+## Checklist
+
+- [ ] I am using the current [`master`](https://github.com/PyPSA/pypsa-eur/tree/master) branch or the latest [release](https://github.com/PyPSA/pypsa-eur/releases). Please indicate.
+- [ ] I am running on an up-to-date [`pypsa-eur` environment](https://github.com/PyPSA/pypsa-eur/blob/master/environment.yaml). Update via `conda env update -f environment.yaml`.
+
+## Describe the Bug
+
+*Please provide a description of what the bug is and add a minimal example/command for reproducing the bug.*
+
+## Error Message
+
+*If applicable, paste any terminal output to help illustrating your problem.*
+*In some cases it may also be useful to share your list of installed packages: `conda list`.*
+
+```
+<paste here>
+```

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: PyPSA Mailing List
+    url: https://groups.google.com/forum/#!forum/pypsa
+    about: Please ask and answer general usage questions here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,15 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: enhancement
+assignees: ''
+
+---
+
+<!-- Please do not post usage questions here. Ask them on the PyPSA mailing list: https://groups.google.com/forum/#!forum/pypsa -->
+
+## Describe the feature you'd like to see
+
+*Please give a clear and concise description and provide context why the feature would be useful.*
+*Also, we'd appreciate any implementation ideas and references you already have.*

.github/pull_request_template.md

@@ -0,0 +1,13 @@
+Closes # (if applicable).
+
+## Changes proposed in this Pull Request
+
+
+## Checklist
+
+- [ ] I tested my contribution locally and it seems to work fine.
+- [ ] Code and workflow changes are sufficiently documented.
+- [ ] Newly introduced dependencies are added to `environment.yaml` and `environment.docs.yaml`.
+- [ ] Changes in configuration options are added in all of `config.default.yaml`, `config.tutorial.yaml`, and `test/config.test1.yaml`.
+- [ ] Changes in configuration options are also documented in `doc/configtables/*.csv` and line references are adjusted in `doc/configuration.rst` and `doc/tutorial.rst`.
+- [ ] A note for the release notes `doc/release_notes.rst` is amended in the format of previous release notes.