enable codecov in GH check #421

Job	Run time
coverage	5m 10s
build (--config=clang-format)	7m 11s
build (--config=clang-tidy)	8m 18s
build (--compilation_mode=opt)	12m 39s
build-without-terminfo (gcc)	7m 30s
build-without-terminfo (clang)	11m 52s
test (gcc)	12m 38s
test (gcc, asan)	11m 50s
test (gcc, tsan)	12m 36s
test (gcc, ubsan)	12m 58s
test (clang)	12m 41s
test (clang, asan)	12m 37s
test (clang, tsan)	12m 36s
test (clang, ubsan)	12m 37s
buildifier	16s
	2h 33m 29s

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