Update MIT-mismatches.xml to include zScore

zscore.mit.edu provides a sleep schedule analysis service. It handles sensitive and private data such as people's bedtime and wake-up time, and unfortunately do not automatically redirect to https, so it is a good idea to include it in the MIT ruleset. It is a relatively trivial change: just changing `http` to `https` will do.
Merge pull request #844 from vulpicastor/patch-1

Update MIT-mismatches.xml to include zScore