Add update Methods for Compilation Context

update method will allow the creation of a new compilation context
based on the current one with new types/names.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/P4Compiler/Program.swift

@@ -168,7 +168,7 @@ public struct Program {
       {
       case Result.Ok((let parser, let updated_context)):
         // Create a new context with the name of the parser that was just compiled in scope.
-        compilation_context = CompilerContext(withNames: updated_context.names.declare(identifier: parser.name, withValue: parser))
+        compilation_context = compilation_context.update(newNames: updated_context.names.declare(identifier: parser.name, withValue: parser))
       case Result.Error(let error): errors.append(error)
       }