[docs] fix a typo

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>

NOTES_TO_PACKAGE_MAINTAINERS

@@ -23,7 +23,7 @@ incompatible with newer versions. Make sure to warn your users
 about it. Plan is to release a stable version (1.0) when
 we are confident that the current implementation is stable enough.
 
-libknet has a lot of build dependencies due to it's modular
+libknet has a lot of build dependencies due to its modular
 implementation. It does not, however, link with all those libraries
 but uses a dlopen model to save runtime resources and provide
 flexibility to users to install only the libraries they are