feat: upgrade ts-relayer dependencies (#2722)

* chore: upgrade `@confio/relayer` to the latest version 0.5.1
* chore: update `@cosmjs` to version 0.28.9
* chore: remove `@cosmjs/launchpad` from dependencies
* chore: add new dependency `@cosmjs/encoding` for relayer
* chore: add `sinon` dependency required to build the relayer
* fix: remove "gasLimit" option from relayer
* fix: update `@cosmjs` to version 0.28.11