[patch edk2-wiki] Update ECC wiki page

[Dandan Bi <dandan.bi@intel.com>]

Update ECC wiki page to record how to solve the
problem “ModuleNotFoundError: No module named 'antlr4'”
when run ECC tool with python3.x.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
---
 ECC-tool.md | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/ECC-tool.md b/ECC-tool.md
index eaf4137..03dbb30 100644
--- a/ECC-tool.md
+++ b/ECC-tool.md
@@ -12,18 +12,27 @@ Steps to run ECC tool:<br>
 **1). Enter edk2 directory, run: **edksetup.bat**** (**on Windows**)<br>
       **Enter edk2 directory, run: **source edksetup.sh**** (**on Linux**)<br>
 
 **2). Then in edk2 directory, you can type "Ecc" to run ECC tool directly**.<br>
 
-**3). If you meet following error:**<br>
+**3). If you meet following errors:**<br>
+**Error 1:**<br>
     **import antlr3**<br>
     **ImportError: No module named antlr3**<br>
 
-Since ECC depends on antlr V3.0.1, you can download it from http://www.antlr3.org/download/Python/ <br>
+This error may be met when you run ECC tool with python 2.x, then ECC depends on antlr V3.0.1, you can download it from http://www.antlr3.org/download/Python/ <br>
 After download and extract it, you can enter the antlr tool directory and run: <br>
 **C:\Python27\python.exe setup.py install** to install it.(**on Windows**) <br>
-**python setup.py install**" to install it, root access may be required.(**on Linux**) <br>
+**python setup.py install** to install it, root access may be required.(**on Linux**) <br>
+
+**Error 2:**<br>
+    **import antlr4 as antlr** <br>
+    **ModuleNotFoundError: No module named 'antlr4'** <br>
+
+This error may be met when you run ECC tool with python 3.x, then ECC depends on antlr4, you can install it through following command.<br>
+**py -3 -m pip install antlr4-python3-runtime** to install it.(**on Windows**) <br>
+**sudo python3 -m pip install antlr4-python3-runtime** to install it. (**on Linux**) <br>
 
 **4). You can type "Ecc -h/Ecc --help" to get the help info of ECC tool**.<br>
 
 **5). Common usage model:**<br>
 **Ecc -c config file  -e exception file  -t  the target directory which need to be scanned by ECC -r the ECC scan result csv file**<br>
-- 
2.18.0.windows.1