fix for yaml swallowing quotes

[esc]

We recent encountered some yaml issues. Imagine a yaml file contains an account
number like 012345678. Since it 'seems' to be a number we might expect it to be
quoted in the final yaml output. However, two things cause this to not happen:

a) The number starts with a leading '0' which is interpreted by Python as
octal.

b) Actually, it can not be octal since it contains the digit '8' and so yaml
says that it must be string and discards the quoting because it is not
ambiguous.

This means that in the final accounts.yaml most accounts are quote except for
those that start with a leading '0' and contain either and '8' or a '9'.

This is an adapted fix inspired by the comments in:

https://bitbucket.org/xi/pyyaml/issues/29/zero-padded-numbers-ending-in-8-or-9-dump

[esc]

cc @schlomo @konz @oliver-schoenherr

Not sure if we actually want this behaviour, but thought I'd push it anyway, just in case.

[schlomo]

IMHO this adds totally unnecessary complexity to the code. Nobody else will ever understand (without a deep dive) exactly what the problem was and how the magic fix works.

So my question would be to find out where the actual problem was or if the problem was only imaginary. For an imaginary problem an imaginary fix might suffice :-)

[snordhausen]

What you are reporting is not a bug. The output produced is valid yaml, and should be interpreted by a yaml parser, not by Python.

[konz]

I suggest removing YAML format altogether. People do weird stuff, e.g. parsing yaml with bash code, importing to Excel sheets - and this will lead to errors with AWS account ids.

Do we know anyone relying on YAML?