Adds towncrier and giles config (#149)

{{ cookiecutter.package_name }}/changelog/README.rst

@@ -0,0 +1,34 @@
+=========
+Changelog
+=========
+
+.. note::
+
+    This README was adapted from the pytest changelog readme under the terms of the MIT licence.
+
+This directory contains "news fragments" which are short files that contain a small **ReST**-formatted text that will be added to the next ``CHANGELOG``.
+
+The ``CHANGELOG`` will be read by users, so this description should be aimed at SunPy users instead of describing internal changes which are only relevant to the developers.
+
+Make sure to use full sentences with correct case and punctuation, for example::
+
+    Add support for Helioprojective coordinates in `sunpy.coordinates.frames`.
+
+Please try to use Sphinx intersphinx using backticks.
+
+Each file should be named like ``<PULL REQUEST>.<TYPE>[.<COUNTER>].rst``, where ``<PULL REQUEST>`` is a pull request number, ``COUNTER`` is an optional number if a PR needs multiple entries with the same type and ``<TYPE>`` is one of:
+
+* ``breaking``: A change which requires users to change code and is not backwards compatible. (Not to be used for removal of deprecated features.)
+* ``feature``: New user facing features and any new behavior.
+* ``bugfix``: Fixes a reported bug.
+* ``doc``: Documentation addition or improvement, like rewording an entire session or adding missing docs.
+* ``deprecation``: Feature deprecation
+* ``removal``: Feature removal.
+* ``trivial``: A change which has no user facing effect or is tiny change.
+
+So for example: ``123.feature.rst``, ``456.bugfix.rst``.
+
+If you are unsure what pull request type to use, don't hesitate to ask in your PR.
+
+Note that the ``towncrier`` tool will automatically reflow your text, so it will work best if you stick to a single paragraph, but multiple sentences and links are OK and encouraged.
+You can install ``towncrier`` and then run ``towncrier --draft`` if you want to get a preview of how your change will look in the final release notes.

{{ cookiecutter.package_name }}/docs/conf.py

@@ -45,6 +45,7 @@
     "sphinx.ext.mathjax",
     "sphinx_automodapi.automodapi",
     "sphinx_automodapi.smart_resolver",
+    "sphinx_changelog",
 ]
 
 # Add any paths that contain templates here, relative to this directory.

{{ cookiecutter.package_name }}/docs/index.rst

@@ -8,6 +8,8 @@ This is the documentation for {{ cookiecutter.package_name }}.
    :maxdepth: 2
    :caption: Contents:
 
+   whatsnew/index
+
 Indices and tables
 ==================
 

{{ cookiecutter.package_name }}/docs/whatsnew/changelog.rst

@@ -0,0 +1,10 @@
+.. _changelog:
+
+**************
+Full Changelog
+**************
+
+.. changelog::
+   :towncrier: ../../
+   :towncrier-skip-if-empty:
+   :changelog_file: ../../CHANGELOG.rst

{{ cookiecutter.package_name }}/docs/whatsnew/index.rst

@@ -0,0 +1,12 @@
+.. _whatsnew:
+
+***************
+Release History
+***************
+
+This page documents the releases for {{ cookiecutter.package_name }}
+
+.. toctree::
+   :maxdepth: 1
+
+   changelog

{{ cookiecutter.package_name }}/pyproject.toml

@@ -42,6 +42,7 @@ tests = [
 docs = [
   "sphinx",
   "sphinx-automodapi",
+  "sphinx-changelog",
   "sunpy-sphinx-theme",
   "packaging",
 ]
@@ -87,3 +88,63 @@ write_to = "{{ cookiecutter.module_name }}/_version.py"
 {%- else -%}
 write_to = "{{ cookiecutter.module_name }}/version.py"
 {%- endif %}
+
+[tool.gilesbot]
+  [tool.gilesbot.pull_requests]
+  enabled = true
+
+  [tool.gilesbot.towncrier_changelog]
+  enabled = true
+  verify_pr_number = true
+  changelog_skip_label = "No Changelog Entry Needed"
+  help_url = "https://github.com/{{ cookiecutter.github_repo | default('sunpy/sunpy') }}/blob/main/changelog/README.rst"
+
+  changelog_missing_long = "There isn't a changelog file in this pull request. Please add a changelog file to the `changelog/` directory following the instructions in the changelog [README](https://github.com/{{ cookiecutter.github_repo | default('sunpy/sunpy') }}/blob/main/changelog/README.rst)."
+
+  type_incorrect_long = "The changelog file you added is not one of the allowed types. Please use one of the types described in the changelog [README](https://github.com/{{ cookiecutter.github_repo | default('sunpy/sunpy') }}/blob/main/changelog/README.rst)"
+
+  number_incorrect_long = "The number in the changelog file you added does not match the number of this pull request. Please rename the file."
+
+# TODO: This should be in towncrier.toml but Giles currently only works looks in
+# pyproject.toml we should move this back when it's fixed.
+[tool.towncrier]
+  package = "{{ cookiecutter.package_name }}"
+  filename = "CHANGELOG.rst"
+  directory = "changelog/"
+  issue_format = "`#{issue} https:github.com/{{ cookiecutter.github_repo | default('sunpy/sunpy') }}/changelog/pull/{issue}>`__"
+  title_format = "{version} ({project_date})"
+
+  [[tool.towncrier.type]]
+  directory = "breaking"
+  name = "Breaking Changes"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "deprecation"
+  name = "Deprecations"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "removal"
+  name = "Removals"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "feature"
+  name = "New Features"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "bugfix"
+  name = "Bug Fixes"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "doc"
+  name = "Documentation"
+  showcontent = true
+
+  [[tool.towncrier.type]]
+  directory = "trivial"
+  name = "Internal Changes"
+  showcontent = true