.pytool/LicenseCheck: Open files in utf-8

The LicenseCheck plugin currently fails if a file contains characters
outside the platform-dependent encoding returned from
locale.getencoding().

This change updates the encoding to utf-8 so the plugin is more
robust while continuing to support backward compatibility with the
ASCII range.

Signed-off-by: Michael Kubacki <[email protected]>

.pytool/Plugin/LicenseCheck/LicenseCheck.py

@@ -70,7 +70,7 @@ def RunBuildPlugin(self, packagename, Edk2pathObj, pkgconfig, environment, PLM,
         temp_diff_output = os.path.join (temp_path, 'diff.txt')
         params = "diff --output={} --unified=0 origin/master HEAD".format(temp_diff_output)
         RunCmd("git", params)
-        with open(temp_diff_output) as file:
+        with open(temp_diff_output, encoding='utf8') as file:
             patch = file.read().strip().split("\n")
         # Delete temp directory
         if os.path.exists(temp_path):