go-toolset:ol8 security update

go-toolset 1.15.14-2 - Revert to Go 1.15.14 - Related: rhbz1995126 - Reverts: rhbz1994087 1.15.15-1 - Rebase to Go 1.15.15 - Resolves: rhbz1994087 - Add reject leading zeros patch - Resolves: rhbz1994010...