reqs: add typing-extension dependency (#1263)

Self is a very useful type to have available, introduced in 3.11. In
Python 3.10 a third-party module is required for the same functionality.
I reckon the extra dependency is worth it for the kind of thing we'd
like to express.

It seems to me like it's necessary to make it a required dependency as
core code should be able to use Self, so users of pip install should
inherit it as well. It's a bit annoying to have a dependency that's only
required for python 3.10 but it seems worth it to me.

---------

Co-authored-by: kingiler <68145845+kingiler@users.noreply.github.com>

requirements.txt

@@ -1,2 +1,3 @@
 pip<24.0
 immutabledict<2.2.6
+typing-extensions>=4.7,<5

xdsl/interpreters/shaped_array.py

@@ -1,11 +1,12 @@
 from __future__ import annotations
 
 import operator
+from dataclasses import dataclass
 from itertools import accumulate, product
 from math import prod
 from typing import Generic, Iterable, TypeAlias, TypeVar
 
-from attr import dataclass
+from typing_extensions import Self
 
 _T = TypeVar("_T")
 
@@ -64,7 +65,7 @@ def indices(self) -> Iterable[tuple[int, ...]]:
         """
         yield from product(*(range(dim) for dim in self.shape))
 
-    def transposed(self, dim0: int, dim1: int) -> ShapedArray[_T]:
+    def transposed(self, dim0: int, dim1: int) -> Self:
         """
         Returns a new ShapedArray, with the dimensions `dim0` and `dim1` transposed.
         """