* Initial preparation of hdf5-1_14_3 release branch for HDF5 1.14.3
release.
Updated configure.ac for release: switched configure default to
production mode and disabled maintainer mode.
Set HDF5_GENERATE_HEADERS to OFF in src/CMakeLists.txt.
Generated release files including Makefile.ins with autogen.sh, autoconf
2.71 and automake 1.16.2.
Incremented version to 1.14.3-2.
* Add hdf5_1_14_3 branch for .github testing.