Fix small typo in _config.yml (pt)
Add languages_heading (pt)
Add credits to _config.yml (pt)
Add unmaintained notice in portuguese (pt)

It's more useful to have an unmaintained notice in portuguese than english.
Add pt/about/website/index.md (pt)
Add /pt/about/logo/ (pt)
Merge pull request #774 from abinoam/feat_pt_update_config_yml

Update _config.yml (pt)