docs: Remove warning which considers v2 as not production ready

docs/03-apis/api-v2/introduction.md

@@ -13,9 +13,6 @@ specification of API V1 was an evolving process, V1 has various
 inconsistencies and peculiarities. With V2, we would like to offer a
 format that is consistent and hence easier to use for a client.
 
-Please note that V2 is still in development. We do not yet recommend
-using it on productive systems.
-
 ## API v2 Path Segment
 
 Every request to API v2 includes `v2` as a path segment, e.g.
@@ -114,8 +111,8 @@ complex schema is used by default in the response, unless the request specifical
 asks for the simple schema. The client can specify the desired schema by using
 an HTTP header or a URL parameter:
 
-  - the HTTP header `X-Knora-Accept-Schema`
-  - the URL parameter `schema`
+- the HTTP header `X-Knora-Accept-Schema`
+- the URL parameter `schema`
 
 Both the HTTP header and the URL parameter accept the values `simple` or
 `complex`.

knora-ontologies/knora-base.ttl

@@ -1820,6 +1820,8 @@
                       owl:cardinality "1"^^xsd:nonNegativeInteger ],
                     [ rdf:type           owl:Restriction ;
                       owl:onProperty     :lastModificationDate ;
+#                      TODO: replace line to make the lastModificationDate mandatory
+#                      owl:cardinality "1"^^xsd:nonNegativeInteger ],
                       owl:maxCardinality "1"^^xsd:nonNegativeInteger ],
                     [ rdf:type           owl:Restriction ;
                       owl:onProperty     :deleteDate ;