Revert "Trimmed the branch to only the 3rdparty/sklearn sub directory"

This reverts commit 0716b1d717b3a48fdc6606c3a5f19bb15e8acec3.
Rebase from 'upstream'
Trimmed the branch to only the 3rdparty/sklearn sub directory
Revert "Trimmed the branch to only the 3rdparty/sklearn sub directory"

This reverts commit 6d60ffced64e7d6df2cf4a51fa349dc7fee361b7.
Rebase from 'upstream' (no changes)
Trimmed the branch to only the 3rdparty/sklearn sub directory