Remove Python35 from Azure and add Python39

.azure-pipelines.yml

@@ -11,14 +11,14 @@ jobs:
 
     strategy:
       matrix:
-        Python35:
-          python.version: '3.5'
         Python36:
           python.version: '3.6'
         Python37:
           python.version: '3.7'
         Python38:
           python.version: '3.8'
+        Python39:
+          python.version: '3.9'
       maxParallel: 4
 
     steps:

MANIFEST.in

@@ -14,7 +14,6 @@ include requirements-dev.txt
 
 graft flaskbb
 graft tests
-graft migrations
 
 prune flaskbb/themes/*/node_modules
 prune flaskbb/themes/*/.sass-cache
@@ -23,3 +22,6 @@ prune flaskbb/themes/*/src/*
 global-exclude __pycache__
 global-exclude *.py[co]
 global-exclude *.sw[a-z]
+global-exclude *.log
+global-exclude .directory
+global-exclude .coverage