Update copy_go_codegen.sh (#1450)

Author: skmcgrail

codegen/copy_go_codegen.sh

@@ -7,5 +7,5 @@ CODGEN_ROOT=$2
 
 REPOTOOLS_VERSION="${REPOTOOLS_VERSION:-latest}"
 
-cd "$1"/internal/repotools
+cd "$1"
 go run github.com/awslabs/aws-go-multi-module-repository-tools/cmd/gomodgen@${REPOTOOLS_VERSION} -build "$CODGEN_ROOT"