Update to new Psr\Http\Message\StreamInterface spec

[phpfui]

New Psr\Http\Message\StreamInterface breaks the code. Apparently this broke 2023-04-18 for my PHPFUI site which updates nightly. I suspect it was caused by a GuzzleHttp dependency that finally allowed my site to be upgraded to the latest StreamInterface.

The issue is now PHP 7.1 is broken. But at this point I think it is worth dropping 7.1 support. There is absolutely no reason for anyone to be on 7.1, or they can lock in an old version.

I did not include that in the PR, but happy to do so.

[zbateson]

Wonderful, thank you!

[phpfui]

Release and rerun the tests on the other two packages to make sure they are now compatible. If not, I can drop 7.1 support on them. Let me know.

[zbateson]

Seems to be all good locally for me at least -- I can't seem to find a way to rerun tests on github without adding a commit, but testing locally on 7.1 worked, as did later versions which included this update.

[phpfui]

OK, good. I can't test below 7.4 without a more advanced setup, but I don't support anything less than 8.0 at this point, so have not bothered with a better setup. At this point, I just drop old versions when they cause any grief. I dropped 8.0 for one of my packages recently for some reason. Not worth spending any time supporting old versions. It either works or is dropped. So much easier!