[ci] powershell can't download lua binaries from sourceforge anymore;… #51

Job	Run time
macOS Build (Debug)	3m 21s
Windows Build (Debug, x86)	3m 43s
macOS Build (Release)	3m 20s
Linux Build (Debug, x86, gcc)	1m 39s
Windows Build (Debug, amd64)	3m 11s
Linux Build (Debug, x86, clang)	1m 30s
Windows Build (Release, x86)	3m 9s
Linux Build (Debug, amd64, gcc)	1m 25s
Windows Build (Release, amd64)	3m 19s
Linux Build (Debug, amd64, clang)	1m 9s
Linux Build (Release, x86, gcc)	1m 49s
Linux Build (Release, x86, clang)	1m 34s
Linux Build (Release, amd64, gcc)	3m 25s
Linux Build (Release, amd64, clang)	1m 32s
	34m 6s

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