Fix main build (#53)

Two issues:
* The action was pointing to matrix.* rather than inputs.* - this worked for PR build which has a matrix, but no main build, which does not. Fixed to inputs.
* Fix _/- typo - the matrix has python-version, while the input has python_version. Fixed to the later.

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Author: thpierce

.github/actions/artifacts_build/action.yml

@@ -38,7 +38,7 @@ runs:
     - name: Set up Python
       uses: actions/setup-python@v4
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: ${{ inputs.python_version }}
 
     - name: Install tox
       shell: bash
@@ -51,11 +51,11 @@ runs:
         path: |
           .tox
           ~/.cache/pip
-        key: v7-build-tox-cache-${{ matrix.python-version }}-${{ inputs.package_name }}-${{ inputs.os }}-${{ hashFiles('tox.ini', 'dev-requirements.txt') }}
+        key: v7-build-tox-cache-${{ inputs.python_version }}-${{ inputs.package_name }}-${{ inputs.os }}-${{ hashFiles('tox.ini', 'dev-requirements.txt') }}
 
     - name: run tox
       shell: bash
-      run: tox -f ${{ matrix.python-version }}-${{ inputs.package_name }} -- -ra --benchmark-json=${{ matrix.python-version }}-${{ inputs.package_name }}-${{ inputs.os }}-benchmark.json
+      run: tox -f ${{ inputs.python_version }}-${{ inputs.package_name }} -- -ra --benchmark-json=${{ inputs.python_version }}-${{ inputs.package_name }}-${{ inputs.os }}-benchmark.json
 
     - name: Configure AWS Credentials
       uses: aws-actions/configure-aws-credentials@v4