Introduce upcrossing analysis module #651

Job	Run time
check-changes	15s
prepare-cache	44m 2s
conda-windows-latest/3.8	29m 14s
pip-windows-latest/3.8	29m 23s
conda-windows-latest/3.9	31m 41s
hindcast-${{ matrix.os }}/${{ matrix.python-version }}	0s
pip-windows-latest/3.9	28m 14s
conda-ubuntu-latest/3.8	13m 15s
pip-ubuntu-latest/3.8	18m 4s
conda-ubuntu-latest/3.9	13m 1s
pip-ubuntu-latest/3.9	15m 43s
conda-macos-latest/3.8	25m 32s
pip-macos-latest/3.8	16m 4s
conda-macos-latest/3.9	13m 47s
pip-macos-latest/3.9	18m 47s
Indicate completion to coveralls.io	0s
	4h 57m 2s

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