Update SimplePie to 1.3.1

[rmccue]

SimplePie 1.3.1 is ​now available with a ​bunch of fixes.

[rmccue]

#22158 was marked as a duplicate.

[rmccue]

#22163 was marked as a duplicate.

[rmccue]

#21990 was marked as a duplicate.

[westi]

#22159 was marked as a duplicate.

[rmccue]

I marked this as has-patch, since it's literally just copying over the 1.3.1 release; making a .diff for it makes no sense. If you really want a patch: ​https://github.com/simplepie/simplepie/compare/1.3...1.3.1.diff

[ryan]

In 22366:

Update SimplePie to 1.3.1. Props rmccue, ocean90. fixes #22321

[ocean90]

Sorry, my patch forgot to include the new ​Exception.php.

[ryan]

In 22469:

Add SimplePie/Exception.php.

Props ocean90
fixes #22321

[nacin]

Now that we've updated to 1.3.1, we can remove the checks added previously for 1.2 -> 1.3 compatibility. They could cause more trouble than they are worth, especially since plugins could potentially include earlier versions.

Debian will not like that create() is still getting called statically, as it'll generate E_STRICT under newer PHP versions. They actually hacked up SimplePie to add in the "static" keyword, then complained when WordPress broke. I want to note this, but this is the least of our concerns.

[nacin]

In 22599:

Remove SimplePie 1.2/1.3 compatibility code no longer needed with 1.3.1. see #22321. see #21183.

[nacin]

#22163 was marked as a duplicate.