Update Debian kernel to 5.6

.github/workflows/debian.yml

@@ -7,8 +7,8 @@ name: Debian
 
 env:
   GPG_KEY_ID: 56C464BAAC421453
-  KERNEL_VERSION: 5.5.13
-  KDEB_PKGVERSION: 5.5.13-1
+  KERNEL_VERSION: 5.6.2
+  KDEB_PKGVERSION: 5.6.2-1
   LOCALVERSION: -surface
 
 jobs: