Prepare for Linux 5.11

This change prepares the master branch for Linux 5.11, which includes
watching for new stable releases.

.github/workflows/watch.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: [ubuntu-latest]
     strategy:
       matrix:
-        branch: ['v5.10.x']
+        branch: ['v5.10.x', 'v5.11.x']
     steps:
     - name: Checkout Sources
       uses: actions/checkout@v2

README.md

@@ -7,6 +7,7 @@ Custom Linux kernels for Promox VE 6.
 3. Linux 5.8 (EOL)
 4. Linux 5.9 (EOL)
 5. Linux 5.10
+6. Linux 5.11
 
 #### Flavors
 1. Proxmox