Use netCDF-c v4.9.3 #321

Job	Run time
static builds (ubuntu-latest, stable)	1m 25s
static builds (windows-latest, stable-msvc)	4m 19s
static builds (windows-latest, stable-gnu)	5m 52s
mpi-runner	1m 28s
static builds (macos-11, stable)	1s
Address sanitizer	1m 23s
conda (ubuntu, conda-forge, stable)	53s
conda (windows, conda-forge, stable)	2m 47s
static builds (macos-latest, stable)	1m 38s
rustfmt	41s
conda (macos, conda-forge, stable)	1m 16s
test apt (stable)	41s
test apt (beta)	40s
test apt (nightly)	38s
	23m 42s

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