Add basic version of PowerShell script execution on Windows

internal/plugin/plugin.go

@@ -33,7 +33,7 @@ func LookPath(name string) (string, error) {
 				exts = append(exts, e)
 			}
 		} else {
-			exts = []string{".com", ".exe", ".bat", ".cmd"}
+			exts = []string{".com", ".exe", ".bat", ".cmd", ".ps1"}
 		}
 		for _, ext := range exts {
 			path := filepath.Join(step.BasePath(), "plugins", fileName+ext)
@@ -54,8 +54,16 @@ func LookPath(name string) (string, error) {
 // it to complete.
 func Run(ctx *cli.Context, file string) error {
 	args := ctx.Args()
-	//nolint:gosec // arguments controlled by step.
-	cmd := exec.Command(file, args[1:]...)
+	cmdName := file
+
+	// if running on Windows and (likely) a PowerShell script, invoke powershell
+	// with the arguments instead of the plugin file directly.
+	if runtime.GOOS == "windows" && filepath.Ext(file) == ".ps1" {
+		cmdName = "powershell"
+		args = append([]string{args[0], "-noprofile", "-nologo", file}, args[1:]...)
+	}
+
+	cmd := exec.Command(cmdName, args[1:]...)
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr