[7.14] Disable Python 3.10 integration tests for now, fix Python 2.7 test suite

Author: sethmlarson

.ci/test-matrix.yml

@@ -12,7 +12,6 @@ PYTHON_VERSION:
   - "3.7"
   - "3.8"
   - "3.9"
-  - "3.10"
 
 PYTHON_CONNECTION_CLASS:
   - Urllib3HttpConnection

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
         python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
         experimental: [false]
         include:
-          - python-version: 3.10.0-beta.2
+          - python-version: 3.10-dev
             experimental: true
 
     runs-on: ubuntu-latest

dev-requirements.txt

@@ -6,6 +6,7 @@ mock
 sphinx<1.7
 sphinx_rtd_theme
 jinja2
+python-dateutil
 
 # No wheels for Python 3.10 yet!
 numpy; python_version<"3.10"