versions.json: set version to 2.9.99 #526

Job	Run time
LP64-WIP	3m 44s
build-windows (imx8 imx8x imx8m imx8ulp)	8m 24s
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	5m 3s
build-windows (mtl)	6m 45s
build-linux (mnfst, mtl)	4m 31s
build-windows (tgl tgl-h)	7m 42s
manifest-check	39s
build-linux (mnfst, lnl)	4m 38s
build-windows (-d, mtl)	7m 37s
build-linux (mnfst, tgl tgl-h)	5m 24s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	3m 32s
build-linux (zmain, mtl)	3m 27s
build-linux (zmain, lnl)	3m 34s
build-linux (zmain, tgl tgl-h)	3m 44s
build-linux (-d, mnfst, mtl)	4m 45s
compare-linux-win	1m 33s
	1h 15m 2s

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