update metadata for er service

Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Drobnak, David <david.drobnak@t-systems.com>
Co-committed-by: Drobnak, David <david.drobnak@t-systems.com>

otc_metadata/data/documents/er-api-ref.yaml

@@ -1,6 +1,5 @@
 ---
 hc_location: api/er
-environment: internal
 html_location: docs/er/api-ref
 link: /enterprise-router/api-ref/
 pdf_name: er-api-ref

otc_metadata/data/documents/er-umn.yaml

@@ -1,6 +1,5 @@
 ---
 hc_location: usermanual/er
-environment: internal
 html_location: docs/er/umn
 link: /enterprise-router/umn/
 pdf_name: er-umn

otc_metadata/data/services/er.yaml

@@ -1,5 +1,5 @@
 ---
-environment: internal
+environment: public
 repositories:
 - environment: internal
   repo: docs/enterprise-router