Fix CI not passing

apparently pandas doesn't build under pypy reliably, so avoid it from
installing automatically in incompatible environments.

Author: mattsta

pyproject.toml

@@ -34,7 +34,7 @@ dev = [
     "mypy>=1.11.0",
     "pytest>=8.0",
     "pytest-asyncio>=0.23",
-    "pandas>=2.2.1,<3.0.0",
+    "pandas>=2.2.1,<3.0.0; implementation_name != 'pypy'",
     "ruff>=0.11.13,<0.12.0",
 ]
 docs = [
@@ -60,7 +60,7 @@ optional = true
 mypy = ">=1.11.0"
 pytest = ">=8.0"
 pytest-asyncio = ">=0.23"
-pandas = "^2.2.1"
+pandas = { version = "^2.2.1", markers = "implementation_name != 'pypy'" }
 ruff = "^0.11.13"