‼️ Switch from virtualenv to venv

Adapt the `VirtualenvProject` project class to rely on using `venv` instead of
`virtualenv`, renaming it to `VenvProject` in the process.

The `venv` package is part of the standard library, whereas `virtualenv` needs
to be installed separtely. This has the clear advantage that `venv` does not
need to be installed. Although `virtualenv` does have some upsides as well,
none of them are particularly relevant for `aiida-project`.

aiida_project/commands/main.py

@@ -93,7 +93,7 @@ def init(shell: Optional[ShellType] = None):
 @app.command()
 def create(
     name: str,
-    engine: EngineType = EngineType.virtualenv,
+    engine: EngineType = EngineType.venv,
     core_version: str = "latest",
     plugins: Annotated[
         List[str], typer.Option("--plugin", "-p", help="Extra plugins to install.")

aiida_project/config.py

@@ -56,7 +56,7 @@ class ProjectDict:
 
     def __init__(self):
         if not self._projects_path.exists():
-            self._projects_path.joinpath("virtualenv").mkdir(parents=True, exist_ok=True)
+            self._projects_path.joinpath("venv").mkdir(parents=True, exist_ok=True)
             self._projects_path.joinpath("conda").mkdir(parents=True, exist_ok=True)
 
     @property

aiida_project/project/__init__.py

@@ -3,20 +3,20 @@
 
 from .base import BaseProject
 from .conda import CondaProject
-from .virtualenv import VirtualenvProject
+from .venv import VenvProject
 
-__all__ = ["BaseProject", "VirtualenvProject"]
+__all__ = ["BaseProject", "VenvProject"]
 
 
 def load_project_class(engine_type: str) -> Type[BaseProject]:
     """Load the project class corresponding the engine type."""
     engine_project_dict = {
-        "virtualenv": VirtualenvProject,
+        "venv": VenvProject,
         "conda": CondaProject,
     }
     return engine_project_dict[engine_type]
 
 
 class EngineType(str, Enum):
-    virtualenv = "virtualenv"
+    venv = "venv"
     conda = "conda"

aiida_project/project/virtualenv.py → aiida_project/project/venv.py

@@ -7,15 +7,15 @@
 from aiida_project.project.base import BaseProject
 
 
-class VirtualenvProject(BaseProject):
-    """An AiiDA environment based on `virtualenv`."""
+class VenvProject(BaseProject):
+    """An AiiDA environment based on `venv`."""
 
-    _engine = "virtualenv"
+    _engine = "venv"
 
     def create(self, python_path: Optional[Path] = None) -> None:
         super().create(python_path=None)
         python = python_path or Path(sys.executable)
-        venv_command = ["virtualenv", f"--python={python.resolve()}", "."]
+        venv_command = [f"{python.resolve()}", "-m", "venv", "."]
         self.venv_path.mkdir(
             exist_ok=True,
             parents=True,