Revert "Bump stack version to 9.1.0 (#1616)" (#1619)

This reverts commit c3f270a.

Author: reakaleek

config/assembler.yml

@@ -32,8 +32,8 @@ environments:
 
 shared_configuration:
   stack: &stack
-    current:  9.1
-    next: main
+    current:  9.0
+    next: 9.1
     edge: main
 
   master: &master

config/versions.yml

@@ -1,7 +1,7 @@
 versioning_systems:
   stack: &stack
     base: 9.0
-    current: 9.1.0
+    current: 9.0.4
 
   # Using an unlikely high version
   # So that our logic that would display "planned" doesn't trigger
@@ -91,3 +91,4 @@ versioning_systems:
   edot_cf_aws:
     base: 0.1
     current: 0.1.6
+