gnu: python-astroid: Update to 2.6.6.

* gnu/packages/python-xyz.scm (python-astroid): Update to 2.6.6.
[propagated-inputs]: Remove python-six.
[native-inputs]: Remove python-dateutil.

gnu/packages/python-xyz.scm

@@ -17080,34 +17080,29 @@ (define-public python2-tracing
     (license license:gpl3+)))
 
 (define-public python-astroid
-  (let ((revision "1")
-        (commit "5f67396894c79c4661e357ec8bb03aa134a51109"))
-    (package
-      (name "python-astroid")
-      (version (git-version "2.4.2" revision commit))
-      (source
-       (origin
-         ;; The current 2.4.2 release doesn't support Python 3.9.
-         (method git-fetch)
-         (uri (git-reference
-               (url "https://github.com/PyCQA/astroid")
-               (commit commit)))
-         (file-name (git-file-name name version))
-         (sha256
-          (base32 "1ir5716wqgz39jva7x9chhjy41yi3n7fkymb8snh5giwig8kyipk"))))
-      (build-system python-build-system)
-      (propagated-inputs
-       `(("python-lazy-object-proxy" ,python-lazy-object-proxy)
-         ("python-six" ,python-six)
-         ("python-wrapt" ,python-wrapt)))
-      (native-inputs
-       `(("python-dateutil" ,python-dateutil)
-         ("python-pytest" ,python-pytest)
-         ("python-pytest-runner" ,python-pytest-runner)))
-      (home-page "https://github.com/PyCQA/astroid")
-      (synopsis "Common base representation of python source code for pylint and
+  (package
+    (name "python-astroid")
+    (version "2.6.6")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/PyCQA/astroid")
+             (commit (string-append "v" version))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1amzf996inwmh4r3mlpzmch60xs6lrg86vppfnwl1y0l8r0y7zxh"))))
+    (build-system python-build-system)
+    (propagated-inputs
+     `(("python-lazy-object-proxy" ,python-lazy-object-proxy)
+       ("python-wrapt" ,python-wrapt)))
+    (native-inputs
+     `(("python-pytest" ,python-pytest)
+       ("python-pytest-runner" ,python-pytest-runner)))
+    (home-page "https://github.com/PyCQA/astroid")
+    (synopsis "Common base representation of python source code for pylint and
 other projects")
-      (description "@code{python-astroid} provides a common base representation
+    (description "@code{python-astroid} provides a common base representation
 of python source code for projects such as pychecker, pyreverse, pylint, etc.
 
 It provides a compatible representation which comes from the _ast module.  It
@@ -17116,8 +17111,8 @@ (define-public python-astroid
 additional methods and attributes for different usages.  They include some
 support for static inference and local name scopes.  Furthermore, astroid
 builds partial trees by inspecting living objects.")
-      (license license:lgpl2.1+)
-      (properties `((python2-variant . ,(delay python2-astroid)))))))
+    (license license:lgpl2.1+)
+    (properties `((python2-variant . ,(delay python2-astroid))))))
 
 (define-public python2-astroid
   (let ((base (package-with-python2