[update-collection-v3] Yaml aliases are expanded

[andrzej-stencel]

Yaml aliases are expanded, which results in duplication and harder comparison of changes.

Input:

sumologic:
  node1: &blueprint
    key1: value1
    key2: value2
  node2:
    <<: *blueprint
    key3: value3

Expected output:

sumologic:
  node1: &blueprint
    key1: value1
    key2: value2
  node2:
    <<: *blueprint
    key3: value3

Actual output:

sumologic:
  node1:
    key1: value1
    key2: value2
  node2:
    key1: value1
    key2: value2
    key3: value3