This reverts commit 00716eb4.

Signed-off-by: Jaime Pérez Crespo <jaime.perez@uninett.no>

* Update Psalm

* Ignore DocblockTypeContradiction and RedundantConditionGivenDocblockType

* Fix Psalm-errors

* Raise minimum PHP-version to 5.6

* Update lock-file accordingly

* Fix phpunit

* Suppress Psalm-issue

Some metadata publishers offer SHA256 fingerprints to validate the
fingerprint of the certificate used to sign metadata. Allow users to
configure the fingerprinting algorithm to facilitate validation.

For backward compatibility, the default algorithm remains SHA1.

It does not seem like something that is normal so a warning seems in
place. However, forbidding it does not add much value since we accept
unsollicited responses (from any idp) anyway.

Closes: #975