fixed issue with windows using bash script

engine/compiler/compiler.go

@@ -310,7 +310,7 @@ func (c *Compiler) Compile(ctx context.Context, args Args) *engine.Spec {
 		dst.Envs = environ.Combine(envs, dst.Envs)
 		dst.Volumes = append(dst.Volumes, mount)
 		dst.Labels = labels
-		setupScript(src, dst, full)
+		setupScript(src, dst, os)
 		setupWorkdir(src, dst, full)
 		spec.Steps = append(spec.Steps, dst)
 

engine/compiler/script.go

@@ -28,8 +28,9 @@ func setupScript(src *resource.Step, dst *engine.Step, os string) {
 // windows operating system.
 func setupScriptWindows(src *resource.Step, dst *engine.Step) {
 	dst.Entrypoint = []string{"powershell", "-noprofile", "-noninteractive", "-command"}
-	dst.Command = []string{"echo $DRONE_SCRIPT | iex"}
+	dst.Command = []string{"echo $Env:DRONE_SCRIPT | iex"}
 	dst.Envs["DRONE_SCRIPT"] = powershell.Script(src.Commands)
+	dst.Envs["SHELL"] = "powershell.exe"
 }
 
 // helper function configures the pipeline script for the