refactor: use lowercase activate.ps1 for all systems

Author: Katze719

src/poetry/console/commands/env/activate.py

@@ -47,11 +47,7 @@ def _get_activate_command(self, env: Env) -> str:
         elif shell in ["csh", "tcsh"]:
             command, filename = "source", "activate.csh"
         elif shell in ["powershell", "pwsh"]:
-            if WINDOWS:
-                command, filename = ".", "Activate.ps1"
-            else:
-                command, filename = ".", "activate.ps1"
-
+            command, filename = ".", "activate.ps1"
         elif shell == "cmd":
             command, filename = ".", "activate.bat"
         else: