v2.6.0

• Appveyor and travis are no longer used in the continuous integration

• setuptools_scm has been removed and replaced by tbump in order to not
  have hidden runtime dependencies to setuptools

• NodeNg, the base node class, is now accessible from astroid or
  astroid.nodes as it can be used for typing.

• Update enum brain to improve inference of .name and .value dynamic class
  attributes

  Closes pylint-dev/pylint#1932
  Closes pylint-dev/pylint#2062
  Closes pylint-dev/pylint#2306

• Removed Repr, Exec, and Print nodes as the ast nodes
  they represented have been removed with the change to Python 3

• Deprecate Ellipsis node. It will be removed with the next minor release.
  Checkers that already support Python 3.8+ work without issues. It's only
  necessary to remove all references to the astroid.Ellipsis node.
  This changes will make development of checkers easier as the resulting tree for Ellipsis
  will no longer depend on the python version. Background: With Python 3.8 the
  ast.Ellipsis node, along with ast.Str, ast.Bytes, ast.Num,
  and ast.NamedConstant were merged into ast.Constant.

• Deprecated Index and ExtSlice nodes. They will be removed with the
  next minor release. Both are now part of the Subscript node.
  Checkers that already support Python 3.9+ work without issues.
  It's only necessary to remove all references to the astroid.Index and
  astroid.ExtSlice nodes. This change will make development of checkers
  easier as the resulting tree for ast.Subscript nodes will no longer
  depend on the python version. Background: With Python 3.9 ast.Index
  and ast.ExtSlice were merged into the ast.Subscript node.

• Updated all Match nodes to be internally consistent.

• Add Pattern base class.