Remove support for Python 3.6

This version goes end-of-life before we will release GROAMCS 2022, so
we should stop testing it. We decided this a long time ago, but didn't
actually do it.

Refs #3708

diff --git a/admin/containers/utility.py b/admin/containers/utility.py
index dfa27e331fadc09d51929f766da9fb470f938653..55f620ee90f4e3316c95c92c52e716bef7ddaf56 100644 (file)
--- a/admin/containers/utility.py
+++ b/admin/containers/utility.py
@@ -135,7 +135,7 @@ parser.add_argument('--doxygen', type=str, nargs='?', const='1.8.5', default=Non
                     help='Add doxygen environment for documentation builds. Also adds other requirements needed for final docs images.')
 
 # Supported Python versions for maintained branches.
-_python_versions = ['3.6.10', '3.7.7', '3.8.2', '3.9.1']
+_python_versions = ['3.7.7', '3.8.2', '3.9.1']
 parser.add_argument('--venvs', nargs='*', type=str, default=_python_versions,
                     help='List of Python versions ("major.minor.patch") for which to install venvs. '
                          'Default: {}'.format(' '.join(_python_versions)))