Drop Python 3.6 support

.github/workflows/build.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       max-parallel: 3
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.7, 3.8, 3.9]
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python ${{ matrix.python-version }}
@@ -29,10 +29,10 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v1
-      - name: Set up Python 3.7
+      - name: Set up Python 3.8
         uses: actions/setup-python@v1
         with:
-          python-version: 3.7
+          python-version: 3.8
       - name: Install dependencies
         run: pip install pandas pytest
       - name: Install package
@@ -106,10 +106,10 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v1
-      - name: Set up Python 3.6
+      - name: Set up Python 3.8
         uses: actions/setup-python@v1
         with:
-          python-version: 3.6
+          python-version: 3.8
       - name: Install dependencies
         run: pip install black==19.10b0 flake8 isort twine
       - name: Check black code style

environment.yml

@@ -20,6 +20,7 @@ dependencies:
   - sphinx=4.0
   - sphinx_rtd_theme=0.5
   - nbsphinx=0.8
+  - pandoc=2.16
   - numpydoc=1.1
   - sphinx-autosummary-accessors=0.2.1
   - matplotlib=3.5

setup.py

@@ -21,8 +21,9 @@
         "License :: OSI Approved :: MIT License",
         "Natural Language :: English",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
     ],
     description="Python utilities for estimating and transforming "
     "rigid body motion.",