Use https instead of http for links in repo description and README

[davidmyersdev]

The repo description as well as the README link out to https://mozilla.github.io/Fira using http instead of https.

[mangla-abhinav]

I would like to take that up!

[mangla-abhinav]

Created a pull request after fixing it.

#238

[mangla-abhinav]

I think it's not possible for me to change the description of the repo. It can only be done with someone having write permissions.

[rtoijala]

The link to http://scripts.sil.org/OFL in the LICENSE file should also be updated to use HTTPS.

[shibam17]

i would like to take this

[96RadhikaJadhav]

The link to http://scripts.sil.org/OFL in the LICENSE file should also be updated to use HTTPS.

I would like to work on it. Can I create a PR for this?