Increase minimal supported version of flake8 and match flake8 requirements to PyLS ones (#805)

Author: ccordoba12

setup.py

@@ -48,21 +48,21 @@
     extras_require={
         'all': [
             'autopep8',
-            'flake8',
-            'mccabe',
-            'pycodestyle',
+            'flake8>=3.8.0',
+            'mccabe>=0.6.0,<0.7.0',
+            'pycodestyle>=2.6.0,<2.7.0',
             'pydocstyle>=2.0.0',
-            'pyflakes>=1.6.0,<2.2.0',
+            'pyflakes>=2.2.0,<2.3.0',
             'pylint',
             'rope>=0.10.5',
             'yapf',
         ],
         'autopep8': ['autopep8'],
-        'flake8': ['flake8'],
-        'mccabe': ['mccabe'],
-        'pycodestyle': ['pycodestyle'],
+        'flake8': ['flake8>=3.8.0'],
+        'mccabe': ['mccabe>=0.6.0,<0.7.0'],
+        'pycodestyle': ['pycodestyle>=2.6.0,<2.7.0'],
         'pydocstyle': ['pydocstyle>=2.0.0'],
-        'pyflakes': ['pyflakes>=1.6.0,<2.2.0'],
+        'pyflakes': ['pyflakes>=2.2.0,<2.3.0'],
         'pylint': ['pylint'],
         'rope': ['rope>0.10.5'],
         'yapf': ['yapf'],

test/plugins/test_flake8_lint.py

@@ -35,7 +35,7 @@ def test_flake8_no_checked_file(config, workspace):
 
     doc = Document('', workspace, DOC)
     diags = flake8_lint.pyls_lint(config, doc)
-    assert diags == []
+    assert 'Error' in diags[0]['message']
 
 
 def test_flake8_lint(config):