add eol validator for ChannelsSchema model

src/image/utils/schema/triggers.py

@@ -32,7 +32,7 @@ class Config:
     def ensure_still_supported(cls, v: datetime) -> datetime:
         """ensure that the end of life isn't reached."""
         if v < datetime.now(timezone.utc):
-            raise ImageReachedEol("This image revision has reached its end of life")
+            raise ImageReachedEol("This track has reached its end of life")
         return v
 
 
@@ -71,6 +71,14 @@ def _check_risks(cls, values: List) -> str:
 
         return values
 
+    @pydantic.validator("end_of_life")
+    @classmethod
+    def ensure_still_supported(cls, v: datetime) -> datetime:
+        """ensure that the end of life isn't reached."""
+        if v < datetime.now(timezone.utc):
+            raise ImageReachedEol("This track has reached its end of life")
+        return v
+
 
 class ImageSchema(pydantic.BaseModel):
     """Validates the schema of the image.yaml files."""