DNSIMPLE: Adopt diff2 in compatibility mode

[tlimoncelli]

Hi @onlyhavecans:

In reference to replacing pkg/diff with the new pkg/diff2 (#1854)

I've introduced a compatibility mode to pkg/diff2 to make it easier for providers to adopt the new system. If you do a diff with "hide whitespace", you'll see the changes are minimal.

I've taken the liberty of providing this PR as a starting point.

Please run the integration tests and let me know the result. (If you're getting this, I probably don't have access to an account on this provider)

Please run:

    go test -v -verbose -provider DNSIMPLE

and

    go test -v -verbose -provider DNSIMPLE -diff2

They should both complete with no failures. Please fix any failures or loop me in for help.

If you are interested in porting to the new pkg/diff2/By*() functions, I'd be glad to accept a PR. However using the compatibility mode is sufficient if all tests pass.

Thanks and happy new years!!!

Tom
@tlimoncelli

[onlyhavecans]

Happy New Year Tom!

I ran the tests, and they all pass. I will work on getting this moved to ByRecord() soon™. I have a busy few weeks ahead of me so it's "soon™", not just "soon"

[tlimoncelli]

Great! I'll merge this and await the rewrite in another PR. No rush. soon™ is good!