Merge pull request #755 from ava-labs/bump-coreth

Bump coreth to v0.3.20

Author: StephenButtolph

scripts/build_coreth.sh

@@ -13,7 +13,7 @@ BUILD_DIR="$AVALANCHE_PATH/build" # Where binaries go
 PLUGIN_DIR="$BUILD_DIR/plugins" # Where plugin binaries (namely coreth) go
 BINARY_PATH="$PLUGIN_DIR/evm"
 
-CORETH_VER="v0.3.19"
+CORETH_VER="v0.3.20"
 
 CORETH_PATH="$GOPATH/pkg/mod/github.com/ava-labs/coreth@$CORETH_VER"