ci: fix kernel image filename extensions in build workflow

Correct the kernel image filename extensions from Image-gz/Image-lz4 to Image.gz/Image.lz4 in the GitHub Actions build workflow to match the actual file naming convention

.github/workflows/build.yml

@@ -503,12 +503,12 @@ 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
+          $MKBOOTIMG --header_version 4 --kernel Image.gz --output boot-gz.img
           $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
+          $MKBOOTIMG --header_version 4 --kernel Image.lz4 --output boot-lz4.img
           $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