Add Ivan to July 2020 WG and add agenda item (#447)

Co-authored-by: Lee Byron <lee@leebyron.com>

Author: IvanGoncharov

agendas/2020-07-02.md

@@ -37,6 +37,7 @@ agenda, edit this file.*
 | Matt Mahoney             | Facebook                 | New York, NY, US
 | Evan Huus                | Shopify                  | Ottawa, ON, CA
 | Andi Marek              | GraphQL-Java                    | Sydney, Australien
+| Ivan Goncharov           | graphql-js               | Lviv, Ukraine
 | Morris Matsa             | IBM                      | Boston, US
 | *ADD YOUR NAME ABOVE TO ATTEND*
 
@@ -68,6 +69,7 @@ Example agenda item:
 1. Review agenda (2m, Lee)
 1. Review previous meeting's action items (5m, Lee)
    - [All action items](https://github.com/graphql/graphql-wg/issues?q=is%3Aissue+label%3A%22Action+item+%3Aclapper%3A%22)
+1. Require argument uniqueness [RFC](https://github.com/graphql/graphql-spec/pull/739) (5m, Ivan)
 1. Moving the `@deprecated directive on Input Fields` RFC to Stage 2 (15m, Stephen)
    - [Initial spec PR (RFC 1)](https://github.com/graphql/graphql-spec/pull/525)
    - [Updated spec PR (RFC 2 Candidate)](https://github.com/graphql/graphql-spec/pull/743/files)