In go 1.16 the `ioutil` package was deprecated and
the functions should be replaced by their equivalents
in either `io` or `os` packages. This means,
that `ioutil.WriteFile` should be replaced by
`os.WriteFile` instead. To account for this change
and to detect incorrect permissions also for `os.WriteFile`
I changed `filePermissions` rule slightly to allows
specifying multiple packages that can contain given
function and that we should check. This workaround
can be removed after a sufficient time has passed
and after it is decided that checking `os.WriteFile`
is enough.
Fixes: https://github.com/securego/gosec/issues/576