versions.json: set version to 2.8.99 #160

Job	Run time
build-linux (mnfst, imx8 imx8x imx8m)	4m 30s
build-windows (imx8 imx8x imx8m)	6m 46s
build-linux (mnfst, mtl)	3m 54s
build-windows (mtl)	5m 16s
build-windows (tgl tgl-h)	6m 19s
build-linux (mnfst, lnl)	3m 52s
build-windows (-d, mtl)	5m 44s
build-linux (mnfst, tgl tgl-h)	4m 58s
build-linux (zmain, imx8 imx8x imx8m)	4m 2s
build-linux (zmain, mtl)	3m 53s
LP64-WIP	3m 21s
build-linux (zmain, lnl)	3m 43s
build-linux (zmain, tgl tgl-h)	4m 44s
manifest-check	40s
build-linux (-d, mnfst, mtl)	4m 4s
compare-linux-win	44s
	1h 6m 30s

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