Fix README.md.

README.md

@@ -9,8 +9,8 @@ files as these can be very large and constructing them can overwhelm the server.
 
 To submit new benchmarks, simply send the new benchmarks to one of the SMT-LIB
 maintainers.  We encourage to distribute benchmarks under the
-[Creative Commons Attribution 4.0 International License]
-(https://creativecommons.org/licenses/by/4.0/ ), but submitters can specify
+[Creative Commons Attribution 4.0 International License](https://creativecommons.org/licenses/by/4.0/),
+but submitters can specify
 their own licence in the benchmark itself using the ```(set-info :license
 "licence string")``` command.