Add LK development wheels to test PyPI (#763)

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**Context:** To externally develop against LightningKokkos requires the
latest package version to be available. Right now, testPyPI wheels exist
for LQ and LG, but not LK. This PR ensures the LK wheels are pushed
alongside LQ with merges to the master branch, ensuring the packages
have the same version

**Description of the Change:** Updates the wheel builder file for x86 to
also push LK to test PyPI.

**Benefits:** Ensures ease of development and testing for Catalyst
against LK.

**Possible Drawbacks:** Installs of LK and LQ during a an upload may see
mismatched package versions, that could create version failures if
depending on the LK package.

**Related GitHub Issues:**

---------

Co-authored-by: ringo-but-quantum <[email protected]>
Co-authored-by: Ali Asadi <[email protected]>

Author: 3 people

.github/CHANGELOG.md

@@ -35,6 +35,9 @@
 
 ### Improvements
 
+* LightningKokkos dev wheels are pushed to https://test.pypi.org/project/PennyLane-Lightning-Kokkos/ upon PR merge.
+  [(#763)](https://github.com/PennyLaneAI/pennylane-lightning/pull/763)
+
 * Change the type of tensor network objects passed to `ObservablesTNCuda` and `MeasurementsTNCuda` class from `StateTensorT` to `TensorNetT`.
   [(#759)](https://github.com/PennyLaneAI/pennylane-lightning/pull/759) 
 

.github/workflows/wheel_linux_x86_64.yml

@@ -200,7 +200,7 @@ jobs:
     strategy:
       matrix:
         arch: [x86_64]
-        pl_backend: ["lightning_qubit"]
+        pl_backend: ["lightning_qubit", "lightning_kokkos"]
     runs-on: ubuntu-latest
 
     if: |
@@ -216,5 +216,5 @@ jobs:
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
           user: __token__
-          password: ${{ secrets.TEST_PYPI_API_TOKEN }}
-          repository-url: https://test.pypi.org/legacy/
+          password: ${{ matrix.pl_backend == "lightning_qubit" && secrets.TEST_PYPI_API_TOKEN || secrets.TEST_PYPI_LKOKKOS_TOKEN }}
+          repository-url: https://test.pypi.org/legacy/

pennylane_lightning/core/_version.py

@@ -16,4 +16,4 @@
    Version number (major.minor.patch[-label])
 """
 
-__version__ = "0.37.0-dev38"
+__version__ = "0.37.0-dev39"