Fix minimal PHP version

Signed-off-by: Christian Wolf <github@christianwolf.email>

appinfo/info.xml

@@ -17,7 +17,7 @@
     <screenshot small-thumbnail="https://raw.githubusercontent.com/nextcloud/cookbook/stable/img/screenshot1_small.png">https://raw.githubusercontent.com/nextcloud/cookbook/stable/img/screenshot1_small.png</screenshot>
     <screenshot>https://raw.githubusercontent.com/nextcloud/cookbook/stable/img/screenshot2.png</screenshot>
     <dependencies>
-        <php min-version="7.3"/>
+        <php min-version="7.4"/>
         <nextcloud min-version="19" max-version="24"/>
     </dependencies>
     <navigations>