Update .gitignore for v9.1.1036

Ignore the src/{LICENSE,README.txt} which are created from shadow
directories.

closes: #16499

Signed-off-by: ichizok <gclient.gaap@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

Author: ichizok

.gitignore

@@ -111,6 +111,8 @@ src/shadow
 src/shadow-*
 src/runtime
 src/pixmaps
+src/LICENSE
+src/README.txt
 
 # other files possibly created by tools
 src/cscope.out