Update optimizer version in README to 0.17.0

Author: justinbarry

README.md

@@ -34,7 +34,7 @@ To compile the contracts, use the CosmWasm optimizer:
 docker run --rm -v "$(pwd)":/code \
   --mount type=volume,source="$(basename "$(pwd)")_cache",target=/target \
   --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
-  cosmwasm/optimizer:0.16.1
+  cosmwasm/optimizer:0.17.0
 ```
 
 ## Development