compiler-families/llvm-compilers: bump gcc version to v7.3.0
# Remember to drop this gnu-compilers dependency in the future,
# when gcc-5.3+ appear in all the targeted Linux distros.
-%global gnuver 7.2.0
+%global gnuver 7.3.0
%global clang_sha b11539abc46cbd19189c5719d1e30539de3a93b9
%global flang_sha 37e86e06f74d9bd91ef6bb511c026753b9124006
