Add new python version of known versions in emsdk.bat (#565)

diff --git a/emsdk.bat b/emsdk.bat
index 0decd1d..5daffe5 100644
--- a/emsdk.bat
+++ b/emsdk.bat
@@ -1,4 +1,9 @@
 :: Find python from an explicit location relative to the Emscripten SDK.

+@IF EXIST "%~dp0python\3.7.4-pywin32_64bit\python.exe" (

+  @SET EMSDK_PY="%~dp0python\3.7.4-pywin32_64bit\python.exe"

+  @GOTO end

+)

+

 @IF EXIST "%~dp0python\3.7.4_64bit\python.exe" (

   @SET EMSDK_PY="%~dp0python\3.7.4_64bit\python.exe"

   @GOTO end