Use platform instead of bootstrap as a dep

mariadb.yaml

@@ -13,11 +13,9 @@ data:
         module: [MIT]
     dependencies:
         buildrequires:
-            bootstrap: f27
+            platform: f28
         requires:
-            platform: f27
-            host: f27
-            networking-base: f27
+            platform: f28
     references:
         community: https://docs.pagure.org/modularity/
         documentation: https://github.com/container-images/mariadb/
@@ -47,11 +45,7 @@ data:
                 %runselftest 0
     components:
         rpms:
-            # mariadb-10.2.9-3.fc28
+            # mariadb-10.2.12-5.fc28
             mariadb:
-                rationale: MariaDB  package.
-                ref: 81336ab97e91b46dc459b15c24fa124cc56370bc
-            # jemalloc-4.5.0-4.fc27
-            jemalloc:
-                rationale: Generated.
-                ref: a1dce39784b3c9cc2bef14027ab9bbc41fdb8c0c
+                rationale: MariaDB package.
+                ref: 39512bdd