MAINTAINERS: remove bbolen

bbolem hasn't reviewed any PRs or engaged in any Zephyr
activity since June 2023.

Recent activities:
  - pr: DNM: Cortex r5 bug
    zephyrproject-rtos#59401
    (2023-06-19T19:41:16Z)
  - review: Review on 'arch: arm: limit FP16 support to Cortex-A or
    Cortex-R'
    zephyrproject-rtos#55101
    (2023-02-23T02:44:44Z)
  - review: Review on 'tests: arm: Increase main stack size with no
    optimizations'
    zephyrproject-rtos#48776 (2022-08-08T14:43:47Z)

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

MAINTAINERS.yml

@@ -223,7 +223,6 @@ ARM arch:
   collaborators:
     - MaureenHelm
     - stephanosio
-    - bbolen
     - ithinuel
   files:
     - arch/arm/