Update action.yml

Author: jonashaag

.github/actions/run-tests/action.yml

@@ -8,7 +8,7 @@ runs:
     - name: Check PyArrow version
       run: |
         # Double check that we have the expected PyArrow
-        mamba list -f pyarrow | grep ${{ matrix.check-pyarrow-version }}
+        mamba list -f pyarrow | grep ${{ inputs.check-pyarrow-version }}
       shell: bash -el {0}
       if: ${{ inputs.check-pyarrow-version }}