Updates osm attribution content
What does this MR do?
Adds "Map data © OpenStreetMap contributors" to the map attribution. According to https://www.openstreetmap.org/copyright this text and a link to this page are required.
How confident are you it won't break things if deployed?
Very
Links to related issues
Checklist
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added a test, or explain why one is not needed/possible... -
no unrelated changes -
asked someone for a code review -
joined #foodsharing-beta channel at https://slackin.yunity.org -
added an entry to CHANGELOG.md (description, merge request link, username(s))