Merge pull request #510 from hyperledger-labs/chore/update-maintainers

Chore: Update MAINTAINERS.md

Author: dzikowski

MAINTAINERS.md

@@ -3,6 +3,6 @@
 ### Active Maintainers
 | name              | Github    |
 |-------------------|-----------|
-| Piotr Hejwowski        | [@hejwo](https://github.com/hejwo) |
-| Jakub Dzikowski | [@dzikowski](https://github.com/dzikowski)  |
-| Grzegorz Hejduk  | [@gzhk](https://github.com/gzhk)  |
+| Piotr Hejwowski   | [@hejwo](https://github.com/hejwo) |
+| Jakub Dzikowski   | [@dzikowski](https://github.com/dzikowski) |
+| Great Umegbewe    | [@umegbewe](https://github.com/umegbewe) |