Add support for plugin packages in Windows

Author: robinmahieu

cogs/plugins.py

@@ -109,14 +109,21 @@ async def load_plugin(self, username, repo, plugin_name):
         if "requirements.txt" in os.listdir(dirname):
             # Install PIP requirements
             try:
-                await self.bot.loop.run_in_executor(
-                    None,
-                    self._asubprocess_run,
-                    f"python3 -m pip install -U -r {dirname}/"
-                    "requirements.txt --user -q -q",
-                )
-                # -q -q (quiet)
-                # so there's no terminal output unless there's an error
+                if os.name == "nt":  # Windows
+                    await self.bot.loop.run_in_executor(
+                        None,
+                        self._asubprocess_run,
+                        f"pip install -r {dirname}/requirements.txt",
+                    )
+                else:
+                    await self.bot.loop.run_in_executor(
+                        None,
+                        self._asubprocess_run,
+                        f"python3 -m pip install -U -r {dirname}/"
+                        "requirements.txt --user -q -q",
+                    )
+                    # -q -q (quiet)
+                    # so there's no terminal output unless there's an error
             except subprocess.CalledProcessError as exc:
                 err = exc.stderr.decode("utf8").strip()