Exclude pymssql for python 3.6 (#1696)

Ref pymssql/pymssql#787

Author: basepi

.ci/.jenkins_exclude.yml

@@ -91,6 +91,8 @@ exclude:
   # pymssql
   - PYTHON_VERSION: pypy-3 # currently fails with error on pypy3
     FRAMEWORK: pymssql-newest
+  - PYTHON_VERSION: python-3.6 # dropped support for py3.6
+    FRAMEWORK: pymssql-newest
   # pyodbc
   - PYTHON_VERSION: pypy-3
     FRAMEWORK: pyodbc-newest