fix: add .\ to gradlew.bat

Author: 0marperez

tests/codegen/smoke-tests/src/test/kotlin/aws/sdk/kotlin/test/codegen/smoketest/SmokeTestE2ETest.kt

@@ -61,7 +61,7 @@ private fun runSmokeTests(
     val sdkRootDir = System.getProperty("user.dir") + "/../../../"
     val processBuilder =
         ProcessBuilder(
-            if (System.getProperty("os.name").contains("Windows", ignoreCase = true)) "gradlew.bat" else "./gradlew",
+            if (System.getProperty("os.name").contains("Windows", ignoreCase = true)) ".\\gradlew.bat" else "./gradlew",
             ":tests:codegen:smoke-tests:services:$service:smokeTest",
             // Make sure unexpected errors are debuggable
             "--stacktrace",