update README. add PyPI publish action.

.github/workflows/publish-pypi.yml

@@ -0,0 +1,25 @@
+name: publish-pypi
+
+on: push
+
+jobs:
+    build-n-publish:
+        name: build and publish
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@master
+            - name: set up Python 3.9
+              uses: actions/setup-python@v3
+              with:
+                  python-version: "3.9"
+            - name: install pypa/build
+              run: >-
+                python -m pip install build --user
+            - name: build a binary wheel and a source tarball
+              run: >-
+                python -m build --sdist --wheel --outdir dist/ .
+            - name: publish distribution to PyPI
+              if: startsWith(github.ref, 'refs/tags')
+              uses: pypa/gh-action-pypi-publish@master
+              with:
+                password: ${{ secrets.PYPI_API_TOKEN }}

README.rst

@@ -36,4 +36,27 @@ Introduction
 ------------
 
 This project implements numerical algorithms for the computation of zeros of holomorphic and the zeros, poles and residues of meromorphic functions.
-It aspires to be a successor to and an extension of the ZEAL (ZEros of AnaLytic functions) package written in Fortran90 by Kravanja, Van Barel, Ragos, Vrahatis, and Zafiropoulos.
+It aspires to be a successor to and an extension of the original ZEAL (ZEros of AnaLytic functions) package written in Fortran90 by Kravanja, Van Barel, Ragos, Vrahatis, and Zafiropoulos [KVanBarelR+00]_.
+The full documentation of this project is hosted on `ReadTheDocs <https://pyzeal.readthedocs.io/en/latest//>`_.
+
+.. [KVanBarelR+00] Kravanja, Van Barel, Ragos, Vrahatis, and Zafiropoulos. ZEAL: A mathematical software package for computing zeros of analytic functions. Computer Physics Communications, 124(2):212–232, 2000.
+
+------------
+Installation
+------------
+
+To install this package you have to clone this repository using ``git clone``.
+Then you can simply use ``pip`` to install the package via
+
+.. code:: bash
+
+  $ python3 -m pip install -e .[dev]
+
+locally in editable mode (``-e``) and including all requirements necessary for development (``[dev``).
+The latter are optional and can be skipped if you just want to use **PyZEAL** as a third-party module in your own applications.
+
+-----------
+Basic Usage
+-----------
+
+