add template for requesting access to credentials store

.github/ISSUE_TEMPLATE/credentials-access.md

@@ -0,0 +1,25 @@
+--
+name: Credential Store Access Request
+about: Request access to the OpenTelemetry credential store
+title: 'REQUEST: Credential Store Access for <USERNAME>'
+labels: area/repo-maintenance
+assignees: ''
+---
+
+<!-- Please remember to change the title of this issue by replacing
+ <USERNAME> with the actual github username -->
+
+### Repository Vault Requested
+
+e.g. https://github.com/open-telemetry/opentelemetry-collector
+
+### Sponsors
+
+Access to shared repository vaults requires a maintainer
+from the requested vault to sponsor the request
+
+### Repository Maintainers
+
+<!-- Tag the current maintainers team here to make them aware of the request. -->
+
+- @open-telemetry/xxx-maintainers