update email (#507)

Signed-off-by: Niclas Schad <niclas.schad@gmail.com>

Chart.yaml

@@ -9,7 +9,7 @@ maintainers:
   - email: thayward@infoblox.com
     name: Tom Hayward
     url: https://github.com/kd7lxl
-  - email: Niclas.Schad@mail.schwarz
+  - email: niclas.schad@stackit.cloud
     name: Niclas Schad
     url: https://github.com/nschad
 name: cortex

MAINTAINERS.md

@@ -1,2 +1,2 @@
-- Niclas Schad, STACKIT <Niclas.Schad@mail.schwarz> ([@nschad](https://github.com/nschad))
+- Niclas Schad, STACKIT <niclas.schad@stackit.cloud> ([@nschad](https://github.com/nschad))
 - Tom Hayward, Infoblox <thayward@infoblox.com> ([@kd7lxl](https://github.com/kd7lxl))

README.md

@@ -13,7 +13,7 @@ Horizontally scalable, highly available, multi-tenant, long term Prometheus.
 | Name | Email | Url |
 | ---- | ------ | --- |
 | Tom Hayward | <thayward@infoblox.com> | <https://github.com/kd7lxl> |
-| Niclas Schad | <Niclas.Schad@mail.schwarz> | <https://github.com/nschad> |
+| Niclas Schad | <niclas.schad@stackit.cloud> | <https://github.com/nschad> |
 
 ## Documentation