Remove attrs dependency and migrate to dataclasses

- Remove attrs from base requirements and constraints
- Replace attr.s decorator with @DataClass in memory_plan.py
- Simplify Region class definition using dataclass

python/gen_requirements.py

@@ -63,7 +63,6 @@
         (
             "Base requirements needed to install tvm",
             [
-                "attrs",
                 "cloudpickle",
                 "decorator",
                 "ml_dtypes",
@@ -236,7 +235,6 @@
 #    here. Include a comment linking to context or explaining why the constraint is in place.
 CONSTRAINTS = [
     ("astroid", None),
-    ("attrs", None),
     ("autodocsumm", None),
     ("black", "==20.8b1"),
     ("cloudpickle", None),

python/tvm/relay/transform/memory_plan.py

@@ -20,7 +20,7 @@
 """
 from typing import Optional, Dict, List, Tuple
 from collections import defaultdict
-import attr
+from dataclasses import dataclass
 
 from ..expr_functor import ExprMutator
 from .. import op, expr
@@ -41,15 +41,14 @@ def is_primitive(call):
     )
 
 
-@attr.s(auto_attribs=True)
+@dataclass
 class Region:
     """
     Represents a control-free allocation region.
 
     The below pass groups sets of allocations into regions,
     then replaces the region with a single allocation.
     """
-
     var: expr.Var
     size: expr.Expr
     alignment: Optional[expr.Expr]