Remove open source label from Keka

[kidonng]

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• New addition to list
• Fixing bug in existing item in list
• Removing item from list
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From the project README:

Keka started in SourceForge as an open source project. Since 1.0 is a closed code project (one of the reasons) and there're no plans to open the code again.

Don't get me wrong, I love Keka, and it will probably remain free forever, but the fact it is no longer open source is also true. The labels should reflect the latest info.

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