Bump codecov/codecov-action from 1 to 4 #408

Job	Run time
Documentation	5m 16s
Julia 1.6 - ubuntu-latest - x64 - push	8m 39s
Julia 1.6 - ubuntu-latest - x86 - push	10m 32s
Julia 1.6 - macOS-latest - x64 - push	8m 45s
Julia 1.6 - windows-latest - x64 - push	13m 47s
Julia 1.6 - windows-latest - x86 - push	21m 51s
Julia 1 - ubuntu-latest - x64 - push	7m 21s
Julia 1 - ubuntu-latest - x86 - push	9m 2s
Julia 1 - macOS-latest - x64 - push	7m 39s
Julia 1 - windows-latest - x64 - push	8m 36s
Julia 1 - windows-latest - x86 - push	12m 5s
Julia nightly - ubuntu-latest - x64 - push	12m 40s
Julia nightly - ubuntu-latest - x86 - push	7m 14s
Julia nightly - macOS-latest - x64 - push	12m 59s
Julia nightly - windows-latest - x64 - push	13m 59s
Julia nightly - windows-latest - x86 - push	7m 58s
	2h 48m 23s

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