Bump actions/add-to-project from 0.6.0 to 0.6.1 #6097

Job	Run time
Black (Python3.9)	1m 10s
py39-prefetch-coverage (Python3.9, windows-latest)	6m 13s
test-conda-Python3.9	6m 26s
py310-coverage (Python3.10, macos-latest)	8m 14s
test-${{ matrix.tox-env }} (Python${{ matrix.python-version }})	0s
test-conda-Python3.12	7m 25s
py39-coverage-sbck (Python3.9, ubuntu-latest)	5m 31s
py310-coverage-lmoments (Python3.10, ubuntu-latest)	8m 53s
py311-coverage-sbck (Python3.11, ubuntu-latest)	5m 40s
py312-coverage-numba (Python3.12, ubuntu-latest)	6m 20s
notebooks_doctests (Python3.10, ubuntu-latest)	6m 40s
offline-prefetch (Python3.11, ubuntu-latest)	4m 32s
finish	16s
	1h 7m 20s

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