Fix push to pypi

[Ariana-B]

Reason for this pull request

PyPi action is still broken.

Proposed changes

• Put back step to push to test pypi (secrets.TestPyPiToken is missing or invalid, needs to be updated)

• Fix bash syntax for setting push_pypi

  • [ ] Closes #xxxx
  • [x] Tests added / passed
  • [x] Fully documented, including docs/about/whats_new.rst for all changes

---

:books: Documentation preview :books:: https://datacube-core--1496.org.readthedocs.build/en/1496/

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (9924bac) 91.79% compared to head (2f414cd) 91.79%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1496 +/- ## ======================================== Coverage 91.79% 91.79% ======================================== Files 132 132 Lines 14537 14537 ======================================== Hits 13344 13344 Misses 1193 1193 ```

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