Specify eltype for CU1Irrep product iterator #171

Job	Run time
Julia 1.6 - ubuntu-latest - x64	55m 8s
Julia 1.6 - macOS-latest - x64	1h 5m 2s
Julia 1.6 - windows-latest - x64	1h 12m 50s
Julia 1 - ubuntu-latest - x64	43m 35s
Julia 1 - macOS-latest - x64	56m 43s
Julia 1 - windows-latest - x64	50m 56s
Julia nightly - ubuntu-latest - x64	53m 45s
Julia nightly - macOS-latest - x64	1h 5m 39s
Julia nightly - windows-latest - x64	58m 8s
	8h 41m 46s

Provide feedback