fix: generate go client in a subdir (#208)

* Generate go client in a subdir
This makes importing the client easier

* Make it unconfigurable
Let's make clients more opinionated

actions/generate-openapi-clients/generate.sh

@@ -2,7 +2,7 @@
 set -euo pipefail
 
 # Generate Go client (TODO: Add support for other languages)
-GO_DIR="${OUTPUT_DIR}/go"
+GO_DIR="${OUTPUT_DIR}/go/${PACKAGE_NAME}"
 rm -rf "${GO_DIR}"
 java -jar openapi-generator-cli.jar generate \
   -i "${SPEC_PATH}" \
@@ -11,6 +11,7 @@ java -jar openapi-generator-cli.jar generate \
   --git-user-id "grafana" \
   --git-repo-id "${REPO_NAME}/go" \
   --package-name "${PACKAGE_NAME}" \
+  -p isGoSubmodule=true \
   -p disallowAdditionalPropertiesIfNotPresent=false \
   -t "${GITHUB_ACTION_PATH}/templates/go"