Update YAML parser to be able to parse anchors and aliases

[jsangmeister]

According to go-yaml/yaml#298, the go-yaml package is not able to parse the anchor/alias syntax (which exists since 2009: https://yaml.org/)... Additionally, the project does seem to be supported anymore. The last commit is ~2 years old, and the fifth-oldest commit over 3 years. We could look into replacing the package alltogether, e.g. by https://github.com/goccy/go-yaml, which seems to be actively maintained (last release 2 weeks ago). Other, IMO worse alternatives include:

• Forking the repo/hacking the functionality in some other way (overkill for this simple feature)
• Preprocessing the yaml file to manually replace aliases with anchors (overkill and hacky)
• Not using aliases and anchors (possible, but not really a satisfactory solution)