Add pixi to installation instructions

[pavelzw]

No description provided.

[github-actions]

(benchmark 5436503381 / attempt 1)
Base results / Our results / Change

Model	Size	Dump Time	Load Time
sklearn rf 20M	20.8 MiB / 3.0 MiB / 6.87 x	0.03 s / 0.04 s / 1.37 x	0.03 s / 0.03 s / 0.91 x
sklearn rf 20M lzma	6.5 MiB / 2.0 MiB / 3.26 x	13.13 s / 1.41 s / 0.11 x	0.57 s / 0.19 s / 0.33 x
sklearn rf 200M	212.3 MiB / 30.6 MiB / 6.94 x	0.21 s / 0.33 s / 1.55 x	0.26 s / 0.36 s / 1.38 x
sklearn rf 200M lzma	47.5 MiB / 14.6 MiB / 3.25 x	99.87 s / 17.97 s / 0.18 x	4.35 s / 1.43 s / 0.33 x
sklearn rf 1G	1157.5 MiB / 166.8 MiB / 6.94 x	1.43 s / 1.75 s / 1.23 x	1.66 s / 1.81 s / 1.09 x
sklearn rf 1G lzma	257.1 MiB / 98.2 MiB / 2.62 x	526.72 s / 122.22 s / 0.23 x	24.65 s / 8.87 s / 0.36 x
sklearn gb 2M	2.2 MiB / 1.1 MiB / 2.08 x	0.04 s / 0.29 s / 7.45 x	0.04 s / 0.18 s / 4.53 x
sklearn gb 2M lzma	0.6 MiB / 0.2 MiB / 3.82 x	1.06 s / 0.46 s / 0.44 x	0.09 s / 0.15 s / 1.62 x
lgbm gbdt 2M	2.6 MiB / 1.0 MiB / 2.78 x	0.10 s / 0.27 s / 2.69 x	0.01 s / 0.12 s / 9.06 x
lgbm gbdt 2M lzma	0.9 MiB / 0.5 MiB / 1.90 x	1.88 s / 0.58 s / 0.31 x	0.08 s / 0.16 s / 1.92 x
lgbm gbdt 5M	5.3 MiB / 1.9 MiB / 2.81 x	0.19 s / 0.57 s / 3.06 x	0.03 s / 0.25 s / 9.36 x
lgbm gbdt 5M lzma	1.7 MiB / 0.8 MiB / 1.96 x	4.70 s / 1.24 s / 0.26 x	0.16 s / 0.32 s / 2.01 x
lgbm gbdt 20M	22.7 MiB / 7.6 MiB / 3.00 x	0.73 s / 2.14 s / 2.94 x	0.12 s / 1.04 s / 8.98 x
lgbm gbdt 20M lzma	6.3 MiB / 3.0 MiB / 2.09 x	22.79 s / 5.55 s / 0.24 x	0.64 s / 1.31 s / 2.07 x
lgbm gbdt 100M	101.1 MiB / 33.0 MiB / 3.06 x	3.28 s / 9.77 s / 2.98 x	0.57 s / 96.03 s / 167.50 x
lgbm gbdt 100M lzma	25.6 MiB / 10.6 MiB / 2.41 x	108.19 s / 27.38 s / 0.25 x	2.51 s / 24.45 s / 9.72 x
lgbm rf 10M	10.9 MiB / 3.2 MiB / 3.46 x	0.39 s / 0.72 s / 1.83 x	0.05 s / 0.42 s / 9.18 x
lgbm rf 10M lzma	0.7 MiB / 0.4 MiB / 1.85 x	1.84 s / 0.99 s / 0.54 x	0.12 s / 0.45 s / 3.68 x