Use Actions not Travis/Azure in Maintenance Guide (#27)

Update the guide to mention our use of GitHub Actions as CI instead of
Travis and Azure. Move the citation part to the bottom since most of our
job is doing releases.

MAINTENANCE.md

@@ -55,64 +55,24 @@ The main advantages of this are:
 
 ## Continuous Integration
 
-We use TravisCI and Azure Pipelines continuous integration (CI) services to build and
+We use GitHub Actions continuous integration (CI) services to build and
 test the project on Windows, Linux, and Mac.
-The configuration files for these services are `.travis.yml` and `.azure-pipelines.yml`.
-Both rely on the `requirements.txt` file to install the required dependencies using
-conda and the `Makefile` to run the tests and checks.
+The configuration files for this service are in `.github/workflows`.
+They rely on the `requirements.txt`, `requirements-optional.txt`, etc 
+files to install the required dependencies using conda or pip.
 
-Travis also handles all of our deployments automatically:
+The CI jobs include:
 
-* Updating the development documentation by pushing the built HTML pages from the
-  *master* branch onto the `dev` folder of the *gh-pages* branch.
-* Uploading new releases to PyPI (only when the build was triggered by a git tag).
-* Updated the `latest` documentation link to the new release.
+* Running the test suite on multiple combinations of OS, Python version,
+  with and without optional dependencies.
+* Running Black, flake8, and pylint to check the code for style.
+* Building the documentation to make sure it works.
+* Pushing the built documentation HTML to the `gh-pages` branch.
+* Upload source and wheel distributions to TestPyPI (on master) and PyPI
+  (on releases).
 
 This way, most day-to-day maintenance operations are automatic.
 
-The scripts that setup the test environment and run the deployments are loaded from the
-[fatiando/continuous-integration](https://github.com/fatiando/continuous-integration)
-repository to avoid duplicating work across multiple repositories.
-If you find any problems with the test setup and deployment, please create issues and
-submit pull requests to that repository.
-
-
-## Citations
-
-The citation for a package that doesn't have an associated paper will be the
-Zenodo DOI for all versions. This citation will include everyone who has
-contributed to the project and met our [authorship criteria](AUTHORSHIP.md).
-
-Include the following text in the `CITATION.rst` file:
-
-```
-This is research software **made by scientists**. Citations help us justify the
-effort that goes into building and maintaining this project.
-
-If you used this software in your research, please consider
-citing the following source: https://doi.org/10.5281/zenodo.3530749
-
-The link above includes full citation information and export formats (BibTeX,
-Mendeley, etc).
-```
-
-If the project has been publish as an academic paper (for example, on
-[JOSS](https://joss.theoj.org)), **update the `CITATION.rst` to point to the
-paper instead of the Zenodo archive**.
-
-```
-If you used this software in your research, please consider citing the
-following publication:
-
-    <full citation including authors, title, journal, DOI, etc>
-
-This is an open-access publication. The paper and the associated reviews can be
-freely accessed at: https://doi.org/<INSERT-DOI-HERE>
-
-The link above includes full citation information and export formats (BibTeX,
-Mendeley, etc).
-```
-
 
 ## Making a Release
 
@@ -147,7 +107,7 @@ The rest of the process is the same as above.
 1. Generate a list of commits between the last release tag and now:
 
     ```bash
-    git log HEAD...v0.1.2 > changes.txt
+    git log HEAD...v0.1.2 > changes.rst
     ```
 
 2. Edit the changes list to remove any trivial changes (updates to the README, typo
@@ -201,10 +161,10 @@ click on "Draft a new release":
 1. Use the version number (including the `v`) as the "Tag version" and "Release
    title".
 2. Fill the release description with a Markdown version of the **latest**
-   changelog entry (including the DOI badge). The `doc/changes.rst` file can be
+   changelog entry (including the DOI badge). The `changes.rst` file can be
    converted to Markdown using `pandoc`:
    ```
-   pandoc -s doc/changes.rst -o changes.md --wrap=none
+   pandoc -s changes.rst -o changes.md --wrap=none
    ```
 3. Publish the release.
 
@@ -215,7 +175,7 @@ reserved DOI.
 
 ### Update the conda package
 
-After Travis is done building the tag and all builds pass, we need to update
+After CI is done building the tag and all builds pass, we need to update
 the conda package.
 Fortunately, the conda-forge bot will submit a PR updating the package for us
 (it may take a couple of hours to do so).
@@ -227,3 +187,39 @@ the conda recipe:
 2. If dropping/adding support for Python versions (or version of other
    packages) make sure the correct version restrictions are applied in
    `meta.yaml`.
+
+## Citations
+
+The citation for a package that doesn't have an associated paper will be the
+Zenodo DOI for all versions. This citation will include everyone who has
+contributed to the project and met our [authorship criteria](AUTHORSHIP.md).
+
+Include the following text in the `CITATION.rst` file:
+
+```
+This is research software **made by scientists**. Citations help us justify the
+effort that goes into building and maintaining this project.
+
+If you used this software in your research, please consider
+citing the following source: https://doi.org/10.5281/zenodo.3530749
+
+The link above includes full citation information and export formats (BibTeX,
+Mendeley, etc).
+```
+
+If the project has been publish as an academic paper (for example, on
+[JOSS](https://joss.theoj.org)), **update the `CITATION.rst` to point to the
+paper instead of the Zenodo archive**.
+
+```
+If you used this software in your research, please consider citing the
+following publication:
+
+    <full citation including authors, title, journal, DOI, etc>
+
+This is an open-access publication. The paper and the associated reviews can be
+freely accessed at: https://doi.org/<INSERT-DOI-HERE>
+
+The link above includes full citation information and export formats (BibTeX,
+Mendeley, etc).
+```