Set docs to build based in net 6

Author: egil

docs/site/docfx.json

@@ -14,7 +14,7 @@
       ],
       "dest": "api",
       "properties": {
-        "TargetFramework": "net5.0"
+        "TargetFramework": "net6.0"
       },
       "disableGitFeatures": false,
       "disableDefaultFilter": false
@@ -84,4 +84,4 @@
     "cleanupCacheHistory": true,
     "disableGitFeatures": false
   }
-}
+}