do not read .env file , sync with the bash version (#689)

scripts/ps/test_unit.ps1

@@ -1,15 +1,5 @@
 # Run the unit tests with the race detector and code coverage enabled
 
-$envPath = Join-Path "cmd" "proxy" | Join-Path -ChildPath ".env"
-Get-Content $envPath | ForEach-Object {
-    $line = $_.ToString().Split("=")
-    if ($line.Length -ne 2) {
-        return
-    }
-    $name = $line[0]
-    $val = $line[1]
-
-    [System.Environment]::SetEnvironmentVariable($name, $val)
-}
+if (!(Test-Path env:GO_ENV)) {$env:GO_ENV = "test"}
 
 & go test -mod=vendor -race -coverprofile cover.out -covermode atomic ./...