ci: fix kernel image extensions in build workflow

Correct the kernel image file extensions from '-gz' and '-lz4' to '.gz' and '.lz4' respectively to match the actual file naming convention

.github/workflows/build.yml

@@ -477,12 +477,12 @@ jobs:
           cp ./boot.img ../WKSU-$KSUVER-${{ inputs.android_version }}-${{ inputs.kernel_version }}.$SUBLEVEL_FOR_NAME-${{ inputs.os_patch_level }}-boot.img
           
           echo "Building boot-gz.img"
-          $MKBOOTIMG --header_version 4 --kernel Image-gz --output boot-gz.img --ramdisk out/ramdisk --os_version 12.0.0 --os_patch_level "${{ inputs.os_patch_level }}"
+          $MKBOOTIMG --header_version 4 --kernel Image.gz --output boot-gz.img --ramdisk out/ramdisk --os_version 12.0.0 --os_patch_level "${{ inputs.os_patch_level }}"
           $AVBTOOL add_hash_footer --partition_name boot --partition_size $((64 * 1024 * 1024)) --image boot-gz.img --algorithm SHA256_RSA2048 --key $BOOT_SIGN_KEY_PATH
           cp ./boot-gz.img ../WKSU-$KSUVER-${{ inputs.android_version }}-${{ inputs.kernel_version }}.$SUBLEVEL_FOR_NAME-${{ inputs.os_patch_level }}-boot-gz.img
           
           echo "Building boot-lz4.img"
-          $MKBOOTIMG --header_version 4 --kernel Image-lz4 --output boot-lz4.img --ramdisk out/ramdisk --os_version 12.0.0 --os_patch_level "${{ inputs.os_patch_level }}"
+          $MKBOOTIMG --header_version 4 --kernel Image.lz4 --output boot-lz4.img --ramdisk out/ramdisk --os_version 12.0.0 --os_patch_level "${{ inputs.os_patch_level }}"
           $AVBTOOL add_hash_footer --partition_name boot --partition_size $((64 * 1024 * 1024)) --image boot-lz4.img --algorithm SHA256_RSA2048 --key $BOOT_SIGN_KEY_PATH
           cp ./boot-lz4.img ../WKSU-$KSUVER-${{ inputs.android_version }}-${{ inputs.kernel_version }}.$SUBLEVEL_FOR_NAME-${{ inputs.os_patch_level }}-boot-lz4.img