Merge pull request #40 from oscarbenjamin/pr_gmp

fix: use GMP rather than MPIR for Linux wheels

Author: oscarbenjamin

bin/cibw_before_all_linux.sh

@@ -2,5 +2,5 @@
 
 yum install -y xz
 bin/build_dependencies_unix.sh\
-  --gmp mpir\
+  --gmp gmp\
   --host x86_64-pc-linux-gnu