update URL of NetCDF release v4.4.0-rc5

Author: wkliao

index.html

@@ -93,7 +93,7 @@ <h2>A Brief Background About NetCDF</h2>
 NetCDF has also included a dispatcher that enables parallel I/O operations on
 files in classic formats (CDF-1 and 2) through PnetCDF. Official support for
 the CDF-5 format started in the
-<a href="https://github.com/Unidata/netcdf-c/blob/v4.4.0/RELEASE_NOTES">release of NetCDF 4.4.0</a>.
+<a href="https://github.com/Unidata/netcdf-c/releases/tag/v4.4.0-rc5">release of NetCDF 4.4.0</a>.
 </p>
 <p>
 Note NetCDF now can be built with PnetCDF as its sole parallel I/O mechanism by