Update redocly.yaml for v2

https://redocly.com/docs/cli/guides/migrate-to-v2#configuration-changes

Build REST Reference…
[1] ../../home/runner/work/documentation-developer/documentation-developer/tools/api_refs/redocly.yaml:1:1 at #/theme

Property `theme` is not expected here.

1 | theme:
2 |   openapi:
3 |     hideHostname: true

Warning was generated by the configuration struct rule.

⚠️ Your config has 1 warning.

Author: adriendupuis

tools/api_refs/redocly.yaml

@@ -1,7 +1,6 @@
-theme:
-  openapi:
-    hideHostname: true
-    theme:
-      logo:
-        maxWidth: '76px!important'
-        maxHeight: '26px'
+openapi:
+  hideHostname: true
+  theme:
+    logo:
+      maxWidth: '76px!important'
+      maxHeight: '26px'