message: In INSTALL, add HYPRE version requirement for mixedint support.
diff: @@ -539,7 +539,8 @@ The specific libraries and their options are:
  See also the "Specific options for hypre" section at the end of this file.
  URL: https://github.com/hypre-space/hypre and https://www.llnl.gov/casc/hypre
  Options: HYPRE_OPT, HYPRE_LIB.
  - Versions: HYPRE >= 2.10.0b.
  + Versions: HYPRE >= 2.10.0b,
  + HYPRE >= 2.20.0 for '--enable-mixedint' support.
  - METIS, used when MFEM_USE_METIS = YES. If using METIS 5, set
  MFEM_USE_METIS_5 = YES (default is to use METIS 4).
  