Update petsc version installing_with_spack.md

[nedpfeiffer]

Merge request type

• [ ] New feature
• [ ] Resolves bug
• [x] Documentation
• [ ] Other

Relates to

• [ ] OPFLOW
• [ ] SOPFLOW
• [ ] SCOPFLOW
• [ ] TCOPFLOW
• [ ] CMake build system
• [ ] Spack configuration
• [x] Manual
• [ ] Web docs
• [ ] Other

This MR updates

• [ ] Header files
• [ ] Source code
• [ ] CMake build system
• [ ] Spack configuration
• [ ] Web docs
• [x] Manual
• [ ] Other

Summary

It appears the Spack installation instructions are outdated. I received the following error:

ubuntu@workstation:~$ spack install exago@develop%gcc \
  ^openmpi ^ipopt@3.12.10+coinhsl~mumps ^coinhsl+blas \
  ^petsc@3.13.6+mpi~hypre~superlu-dist~mumps+shared
==> Error: concretization failed for the following reasons:

   1. Cannot select a single "version" for package "petsc"
   2. Cannot satisfy 'petsc@:3.13'
   3. Cannot satisfy 'petsc@3.20'
   4. Cannot satisfy 'petsc@3.19:'
   5. Cannot satisfy 'petsc@3.18:'
   6. Cannot satisfy 'petsc@3.13:3.14'
   7. Cannot satisfy 'petsc@3.13.6'
   8. Cannot satisfy 'petsc@3.11:3.13'
   9. Cannot satisfy 'petsc@3.19:'
        required because exago depends on petsc@3.19: when @1.6: 
          required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly 
   10. Cannot satisfy 'petsc@3.13.6'
        required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly 
   11. Cannot satisfy 'petsc@3.19:' and 'petsc@3.13.6
        required because exago depends on petsc@3.19: when @1.6: 
          required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly 
        required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly 
   12. Cannot satisfy 'petsc@3.13.6' and 'petsc@3.19:
        required because exago depends on petsc@3.19: when @1.6: 
          required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly 
        required because exago@develop%gcc ^coinhsl+blas ^ipopt@3.12.10+coinhsl~mumps ^openmpi ^petsc@3.13.6~hypre+mpi~mumps+shared~superlu-dist requested explicitly

Specifying petsc version 3.19 as the required version allowed me to continue installation.

[abhyshr]

@cameronrutherford @jaelynlitz : Can you take a look at this PR when you get a chance.

[cameronrutherford]

I'll wait for @jaelynlitz to get back from vacation to give a second opinion, but thanks for this @nedpfeiffer!! Great catch