MINOR: Fix DOAP syntax (#16472)

xmlns strings need to match exactly, and these vocabularies are defined with `http` namespace strings, so we need to follow that.

Reviewers: Mickael Maison <[email protected]>

Author: raboof

doap_Kafka.rdf

@@ -2,9 +2,9 @@
 <?xml-stylesheet type="text/xsl"?>
 <rdf:RDF xml:lang="en"
          xmlns="http://usefulinc.com/ns/doap#"
-         xmlns:rdf="https://www.w3.org/1999/02/22-rdf-syntax-ns#"
-         xmlns:asfext="https://projects.apache.org/ns/asfext#"
-         xmlns:foaf="https://xmlns.com/foaf/0.1/">
+         xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns:asfext="http://projects.apache.org/ns/asfext#"
+         xmlns:foaf="http://xmlns.com/foaf/0.1/">
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