small change in docker enos build (#6120)

* small change in docker build to enable enos github runner

enos/modules/build_boundary_docker_local/build.sh

@@ -10,6 +10,11 @@ pushd "${root_dir}" > /dev/null
 
 # make docker image
 export DEV_DOCKER_GOARCH=$(uname -m)
+# x86_64 is the output of `uname -m` on github actions runners
+# but the go requires goarch to be amd64
+if [[ $DEV_DOCKER_GOARCH == "x86_64" ]]; then
+   export DEV_DOCKER_GOARCH="amd64"
+fi
 export IMAGE_TAG_DEV="${IMAGE_NAME}"
 make build-ui docker-build-dev