Fix 'read without -r will mangle backslashes.' issue in activity.sh

[CodeFactor](https://www.codefactor.io/repository/github/ccdd13/github-activity-bash-script) found an issue: read without -r will mangle backslashes.

It's currently on:
[activity.sh:206
](https://www.codefactor.io/repository/github/ccdd13/github-activity-bash-script/source/main/activity.sh#L206)