Set minimum supported python version to 3.8

Author: arpastrana

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.8]
 
     steps:
       - uses: actions/checkout@v2

README.rst

@@ -28,10 +28,6 @@ COMPAS CEM
    :target: https://zenodo.org/badge/latestdoi/278780552
    :alt: Zenodo DOI
 
-.. image:: https://img.shields.io/twitter/follow/compas_dev?style=social
-   :target: https://twitter.com/compas_dev
-   :alt: Twitter follow
-
 .. end-badges
 
 .. _COMPAS: https://compas.dev/
@@ -98,7 +94,7 @@ If no errors show up, celebrate 🎉! You have a working installation of **COMPA
 Grasshopper plugin
 ------------------
 
-**Warning**: Note that `Grasshopper`_ plugin of ****COMPAS CEM** is only supported in **Rhino 7**.
+**Warning**: Note that `Grasshopper`_ plugin of **COMPAS CEM** is only supported in **Rhino 6** and **Rhino 7**.
 
 Once **COMPAS CEM** was installed from the comment line, we can additionally link it to `Rhino`_ and use it as `Grasshopper`_ plugin:
 

setup.py

@@ -46,8 +46,6 @@ def read(*names, **kwargs):
         "Operating System :: Microsoft :: Windows",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: Implementation :: CPython",
@@ -61,7 +59,7 @@ def read(*names, **kwargs):
     include_package_data=True,
     zip_safe=False,
     install_requires=requirements,
-    python_requires=">=3.6",
+    python_requires=">=3.8",
     extras_require=optional_requirements,
     entry_points={
         "console_scripts": [],