Update humanmade/wp-simple-saml requirement from ~0.5.0 to ~0.5.1

Updates the requirements on [humanmade/wp-simple-saml](https://github.com/humanmade/wp-simple-saml) to permit the latest version.
- [Release notes](https://github.com/humanmade/wp-simple-saml/releases)
- [Commits](humanmade/wp-simple-saml@0.5.0...0.5.1)

---
updated-dependencies:
- dependency-name: humanmade/wp-simple-saml
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

composer.json

@@ -17,7 +17,7 @@
 	},
 	"require": {
 		"php": ">=7.1",
-		"humanmade/wp-simple-saml": "~0.5.0"
+		"humanmade/wp-simple-saml": "~0.5.1"
 	},
 	"extra": {
 		"altis": {