Fix compiler warnings #61

Job	Run time
build-and-test-alpine (16)	2m 43s
build-and-test-alpine (18)	2m 45s
build-and-test (16.x, ubuntu-latest)	2m 2s
build-and-test-alpine (20)	2m 52s
build-and-test (16.x, macos-latest)	5m 0s
build-and-test (16.x, windows-latest)	5m 26s
build-and-test (18.x, ubuntu-latest)	2m 5s
build-and-test (18.x, macos-latest)	5m 59s
build-and-test (18.x, windows-latest)	6m 23s
build-and-test (20.x, ubuntu-latest)	2m 8s
build-and-test (20.x, macos-latest)	2m 31s
build-and-test (20.x, windows-latest)	5m 48s
	45m 42s

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