Update CIME tag required

[manishvenu]

1. Fast Tests Pass (see CI)
2. Slow Tests Pass except for two pre-existing failures
3. Both docs cases pass.

[manishvenu]

Preexisting slow test failure on main, "FAILED tests/3_system/test_f2000_custom_grid.py::test_custom_f2000_new_mom6_grid_modified_clm_grid - ProConPy.dev_utils.ConstraintViolation: 4x5 not an option for CUSTOM_ATM_GRID"

[manishvenu]

failure sometimes that is unrelated to cime6.4.1. "FAILED tests/3_system/test_f2000_custom_grid.py::test_custom_f2000_modified_clm_grid - FileNotFoundError: [Errno 2] No such file or directory: '/glade/work/manishrv/installs/full_regional_cesm/visualCaseGen/tests/temp/tmpbrv4pcyj'"

caused because

but CIME ate the z5:

CIME reserve z in a resolution alias to mean "N atmosphere levels" test and the test hands it a tempfile.mkdtemp name. Roughly 5% of random tmpXXXXXXXX names contain a z followed by a digit, so this test fails nondeterministically on any branch. I verified the regex reproduces the exact mangling.

[manishvenu]

So slow & fast pass (at least the tests that previously passed)

[manishvenu]

Both cases in the docs ran!

[alperaltuntas]

One thing to fix before merge: docs/installation.rst (lines 4, 34, 35) and docs/open.rst (line 67) still reference cesm3_0_alpha09d.