Format project with black (#467)

Format with line length 110 to match flake8

make black part of linting check

Update travis spec for updated black requirements

Add diff output for black on failure

update changelog

vcr/request.py

@@ -15,7 +15,7 @@ class Request(object):
     def __init__(self, method, uri, body, headers):
         self.method = method
         self.uri = uri
-        self._was_file = hasattr(body, 'read')
+        self._was_file = hasattr(body, "read")
         if self._was_file:
             self.body = body.read()
         else:
@@ -40,13 +40,14 @@ class Request(object):
     @body.setter
     def body(self, value):
         if isinstance(value, text_type):
-            value = value.encode('utf-8')
+            value = value.encode("utf-8")
         self._body = value
 
     def add_header(self, key, value):
-        warnings.warn("Request.add_header is deprecated. "
-                      "Please assign to request.headers instead.",
-                      DeprecationWarning)
+        warnings.warn(
+            "Request.add_header is deprecated. " "Please assign to request.headers instead.",
+            DeprecationWarning,
+        )
         self.headers[key] = value
 
     @property
@@ -63,7 +64,7 @@ class Request(object):
         port = parse_uri.port
         if port is None:
             try:
-                port = {'https': 443, 'http': 80}[parse_uri.scheme]
+                port = {"https": 443, "http": 80}[parse_uri.scheme]
             except KeyError:
                 pass
         return port
@@ -95,10 +96,10 @@ class Request(object):
 
     def _to_dict(self):
         return {
-            'method': self.method,
-            'uri': self.uri,
-            'body': self.body,
-            'headers': {k: [v] for k, v in self.headers.items()},
+            "method": self.method,
+            "uri": self.uri,
+            "body": self.body,
+            "headers": {k: [v] for k, v in self.headers.items()},
         }
 
     @classmethod