DIFF of WORD and EXCEL files by merge request

I want to get DIFF of WORD and EXCEL files by merge request in GITLAB.

In git, it is possible to get DIFF as follows, but in gitlab, where should I set .gitattribute and .gitconfig?
<.gitattributes>
*.docx diff=tika
*.pptx diff=tika
*.xlsx diff=tika

<.gitconfig>
[diff “tika”].
binary = true
textconv = java -Dfile.encoding=UTF-8 -jar tika-app-2.6.0.jar -t