Remove unused keywords from package.json

Signed-off-by: Gururaj Gurram <143020143+gururaj1512@users.noreply.github.com>

Author: gururaj1512

lib/node_modules/@stdlib/plot/vega/transform/aggregate/ctor/package.json

@@ -52,9 +52,8 @@
     "stdlib",
     "plot",
     "vega",
-    "signal",
-    "reference",
-    "expression",
+    "transform",
+    "aggregate",
     "constructor",
     "ctor"
   ],