Add a `value` builtin constructor to handle the `=` sign

[jonapich]

fixes #89

There's an alternative fix, we can remove the implicit_loader from resolver.py instead of mapping 'tag:yaml.org,2002:value' to the string resolver.

[hassenius]

This exact issue is affecting us too (with exactly the same CRD.. :) )

[jonapich]

I guess it's worth to mention a local workaround: https://github.com/yaml/pyyaml/issues/89#issuecomment-1124189214

[spacether]

@nitzmahone any chance that we can get a review and merge on this? This issue came up for me too and the issue has 10+ thumbs ups