docs: fix url to point to new repo

Author: boriel

docs/index.md

@@ -74,7 +74,7 @@ Boriel BASIC was designed from the base as a Retargeable Compiler, so it should
 it to other architectures. This is `work in progress`. See [other architectures](other_architectures.md) for more info.
 
 ## Contributing
-You can issue a Pull Request to the [GitHub repository](https://github.com/boriel/zxbasic), report bugs in the forum
+You can issue a Pull Request to the [GitHub repository](https://github.com/boriel-basic/zxbasic), report bugs in the forum
 when using the compiler, suggest new features...
 
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