chore: update WSL2 kernel configuration to version 6.18.20.1

- bump default kernel branch in README and build workflow to `linux-msft-wsl-6.18.y`
- update kernel configuration files to reflect the new version
- adjust fetch script to download the latest WSL2 kernel config

Signed-off-by: Pavel Pikta <pavel_pikta@epam.com>

Author: pavelpikta

.github/workflows/build.yml

@@ -7,7 +7,7 @@ on:
       kernelBranch:
         description: "WSL2-Linux-Kernel branch"
         required: true
-        default: "linux-msft-wsl-6.6.y"
+        default: "linux-msft-wsl-6.18.y"
         type: string
       build-modules:
         description: "Build modules?"
@@ -107,7 +107,7 @@ jobs:
         if: github.event.inputs.build-modules == 'true'
         run: |
           echo "::group::Build modules"
-          if [[ "${{ github.event.inputs.kernelBranch }}" == "linux-msft-wsl-6.6.y" ]]; then
+          if [[ "${{ github.event.inputs.kernelBranch }}" == "linux-msft-wsl-6.18.y" ]]; then
             make -j$(nproc) INSTALL_MOD_PATH="$PWD/modules" modules_install
             if [ ! -f "Microsoft/scripts/gen_modules_vhdx.sh" ]; then
               echo "Error: gen_modules_vhdx.sh script not found"
@@ -120,7 +120,7 @@ jobs:
             fi
             echo "modules-built=true" >> $GITHUB_OUTPUT
           else
-            echo "Error: Module VHDX generation is only supported for branch linux-msft-wsl-6.6.y"
+            echo "Error: Module VHDX generation is only supported for branch linux-msft-wsl-6.18.y"
             echo "Current branch: ${{ github.event.inputs.kernelBranch }}"
             exit 1
           fi

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://github.com/pavelpikta/wsl2-kernel-build/actions/workflows/build.yml/badge.svg)](https://github.com/pavelpikta/wsl2-kernel-build/actions/workflows/build.yml)
 [![WSL2](https://img.shields.io/badge/WSL2-Kernel%20Build-0078D4?logo=windows&logoColor=white)](https://github.com/microsoft/WSL2-Linux-Kernel)
 [![Docker](https://img.shields.io/badge/Docker-Compatible-2496ED?logo=docker&logoColor=white)](https://www.docker.com/)
-[![Linux Kernel](https://img.shields.io/badge/Linux%20Kernel-6.6+-FCC624?logo=linux&logoColor=black)](https://www.kernel.org/)
+[![Linux Kernel](https://img.shields.io/badge/Linux%20Kernel-6.18+-FCC624?logo=linux&logoColor=black)](https://www.kernel.org/)
 [![Shell Script](https://img.shields.io/badge/Shell-Bash-4EAA25?logo=gnu-bash&logoColor=white)](https://www.gnu.org/software/bash/)
 
 A repository for building WSL2 Linux kernels with Docker compatibility and BBR (Bottleneck Bandwidth and RTT) support. This project provides automated tools and configurations to patch Microsoft's WSL2 kernel source with the necessary kernel options required for running Docker and improving network performance.
@@ -85,7 +85,7 @@ The script will:
 2. Select the **Build** workflow
 3. Click **Run workflow**
 4. Configure the build parameters:
-   - **kernelBranch**: WSL2-Linux-Kernel branch (default: `linux-msft-wsl-6.6.y`)
+   - **kernelBranch**: WSL2-Linux-Kernel branch (default: `linux-msft-wsl-6.18.y`)
    - **build-modules**: Whether to build kernel modules (default: `false`)
    - **custom-config**: Use custom config from this repository (default: `false`)
 5. Click **Run workflow**