[V3] Update black version and reformat (#1745)

* Update black version and reformat

* Pin black in extras_require

redbot/cogs/downloader/errors.py

@@ -17,6 +17,7 @@ class DownloaderException(Exception):
     """
     Base class for Downloader exceptions.
     """
+
     pass
 
 
@@ -31,6 +32,7 @@ class InvalidRepoName(DownloaderException):
     Throw when a repo name is invalid. Check
     the message for a more detailed reason.
     """
+
     pass
 
 
@@ -39,6 +41,7 @@ class ExistingGitRepo(DownloaderException):
     Thrown when trying to clone into a folder where a
     git repo already exists.
     """
+
     pass
 
 
@@ -47,6 +50,7 @@ class MissingGitRepo(DownloaderException):
     Thrown when a git repo is expected to exist but
     does not.
     """
+
     pass
 
 
@@ -54,6 +58,7 @@ class CloningError(GitException):
     """
     Thrown when git clone returns a non zero exit code.
     """
+
     pass
 
 
@@ -62,6 +67,7 @@ class CurrentHashError(GitException):
     Thrown when git returns a non zero exit code attempting
     to determine the current commit hash.
     """
+
     pass
 
 
@@ -70,6 +76,7 @@ class HardResetError(GitException):
     Thrown when there is an issue trying to execute a hard reset
     (usually prior to a repo update).
     """
+
     pass
 
 
@@ -77,6 +84,7 @@ class UpdateError(GitException):
     """
     Thrown when git pull returns a non zero error code.
     """
+
     pass
 
 
@@ -84,6 +92,7 @@ class GitDiffError(GitException):
     """
     Thrown when a git diff fails.
     """
+
     pass
 
 
@@ -91,4 +100,5 @@ class PipError(DownloaderException):
     """
     Thrown when pip returns a non-zero return code.
     """
+
     pass