Add Adyen as known instance of Maturity Model (#863)

* Adds Adeyn as known instance of Maturity Model
* Adds custom vale vocabulatory. Adding Adyen.

---------

Co-authored-by: Sebastian Spier <github@spier.hu>

Author: tsadler1988

.github/vale/config/vocabularies/Base/accept.txt

@@ -0,0 +1 @@
+Adyen

.vale.ini

@@ -3,6 +3,8 @@ MinAlertLevel = suggestion
 
 Packages = https://github.com/InnerSourceCommons/isc-styles/releases/latest/download/ISC.zip
 
+Vocab = Base
+
 [*]
 BasedOnStyles = ISC
 

patterns/2-structured/maturity-model.md

@@ -213,6 +213,7 @@ long term.
 * **Zylk**
 * **Bitergia**
 * **Airbus**
+* **Adyen**
 
 ## Authors