Bump debian to 5.5.6.

.github/workflows/debian.yml

@@ -7,8 +7,8 @@ name: Debian
 
 env:
   GPG_KEY_ID: 56C464BAAC421453
-  KERNEL_VERSION: 5.5.4
-  KDEB_PKGVERSION: 5.5.4-1
+  KERNEL_VERSION: 5.5.6
+  KDEB_PKGVERSION: 5.5.6-1
   LOCALVERSION: -surface
 
 jobs: