Fix installation of Imath and libdeflate in windows CI #1003

Job	Run time
Linux.3: static / steps	14m 5s
Linux.2: Debug / steps	24m 8s
Linux.1: Release / steps	13m 47s
Linux.4: threads=OFF / steps	13m 8s
Linux.6: custom namespace / steps	13m 51s
Linux.5: pkgconfig=OFF, examples=OFF, tools=OFF, docs=OFF, internal deflate / steps	4m 17s
Linux.7: clang / steps	13m 57s
Linux.8: vfx2023 / steps	13m 46s
macOS.1: Release / steps	10m 27s
macOS.2: Debug / steps	24m 55s
macOS.3: static / steps	8m 52s
macOS.4: threads=OFF / steps	7m 53s
macOS.5: pkgconfig=OFF, examples=OFF, tools=OFF, docs=OFF, internal imath+deflate / steps	2m 9s
macOS.6: macos-13 / steps	19m 38s
Windows.1: Release / steps	13m 53s
Windows.2: Debug / steps	35m 51s
Windows.3: static / steps	14m 10s
Windows.4: threads=OFF / steps	15m 40s
Windows.5: pkgconfig=OFF, examples=OFF, tools=OFF, docs=OFF, internal imath+deflate / steps	1m 41s
Windows.6: vfx2022 / steps	16m 19s
	4h 42m 27s

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