Fix CI tag for uploading nightly wheels

[JCGoran]

NMODL_NIGHTLY_TAG should've been just TAG.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.30%. Comparing base (c0994d7) to head (d560e14).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1274 +/- ## ======================================= Coverage 86.30% 86.30% ======================================= Files 178 178 Lines 13263 13263 ======================================= Hits 11446 11446 Misses 1817 1817 ```

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[bbpbuildbot]

Logfiles from GitLab pipeline #212425 (:white_check_mark:) have been uploaded here!

Status and direct links:

• :white_check_mark: spack_setup
• :white_check_mark: build:intel
• :white_check_mark: build:nvhpc
• :white_check_mark: test:intel
• :white_check_mark: test:nvhpc