main: Fix license wording
The COPYING file mentions GPLv3+ but this file said GPLv3 only. I'm the sole author of this file, so there aren't any problems fixing this problem summarily.
Closes: #18 (closed)
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The COPYING file mentions GPLv3+ but this file said GPLv3 only. I'm the sole author of this file, so there aren't any problems fixing this problem summarily.
Closes: #18 (closed)