Upgrade to PyYAML 5.1.2 (#8161)
Upgrade to PyYAML 5.1.2 (#8161)


benjyw/pants,wisechengyi/pants,wisechengyi/pants,pantsbuild/pants,tdyas/pants,pantsbuild/pants,benjyw/pants,tdyas/pants,pantsbuild/pants,pantsbuild/pants,tdyas/pants,tdyas/pants,wisechengyi/pants,benjyw/pants,wisechengyi/pants,benjyw/pants,benjyw/pants,wisechengyi/pants,pantsbuild/pants,wisechengyi/pants,pantsbuild/pants,wisechengyi/pants,tdyas/pants,wisechengyi/pants,benjyw/pants,tdyas/pants,jsirois/pants,tdyas/pants,tdyas/pants,jsirois/pants,wisechengyi/pants,pantsbuild/pants,benjyw/pants,tdyas/pants,jsirois/pants