Bump default Linux tag to v6.19

Author: theihor

.github/workflows/vmlinux.h.yml

@@ -11,7 +11,7 @@ on:
         description: 'Kernel version (Git tag/ref)'
         required: true
         # Keep in sync with string used in `checkout` invocation below.
-        default: 'v6.18'
+        default: 'v6.19'
   workflow_call:
 
 jobs:
@@ -37,7 +37,7 @@ jobs:
         uses: actions/checkout@v6
         with:
           repository: 'torvalds/linux'
-          ref: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.kernel-ref || 'v6.18' }}
+          ref: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.kernel-ref || 'v6.19' }}
           fetch-depth: 1
           path: linux/