yamllint: fix all yamllint comments errors

Fix all hyphens errors detected by yamllint:

yamllint -f parsable -c .yamllint $( find -regex '.*\.y[a]*ml' ) | \
  grep '(comments)'

Default config would be to require two spaces after the start of the
comment, proposing to keep it on 1, inline with the Linux binding
config, that is:

```
-  comments:
-    min-spaces-from-content: 1
```

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>