Normalize META.yml indentation

[foolip]

When working on #2196 I noticed different indentation in different files, which made it harder to work with the files.

Could we normalize the formatting of META.yml files and enforce that formatting in the lint?

@KyleJu WDYT?

P.S. I thought there was already an issue about this but I couldn't find it. Sorry if it is nevertheless a dupe of some existing issue.

[KyleJu]

Yea I think there was issue where PRs create huge diff after the indentation changes. #2207 all the gecko updates have less indentation than the default one. Let me find a way to enforce the format in the lint

[foolip]

Oh, does the Gecko sync bot not use the API for updating metadata then?

[KyleJu]

Oh, does the Gecko sync bot not use the API for updating metadata then?

nope I think they use a separate script. I am unsure what YAML library they use, which leads to a difference in formatting