mesh11sd: update to version 3.1.0

mesh11sd: update to version 3.1.0

Maintainer: Rob White rob@blue-wave.net

Compile tested: All

Run tested: arm_cortex-a7_neon-vfpv4, mipsel_24kc, mips_24kc, aarch64_cortex-a53, x86-64
    On 23.5 and master/snapshot.

Description:
    mesh11sd (3.1.0)
    This release contains new functionality and numerous fixes.
    New functionality includes support of non-mesh segments of backhaul
    with blocking of bridge loops and spanning tree priority settable in the configuration

Details can be found here:
    https://github.com/openNDS/mesh11sd/releases/tag/v3.1.0

Signed-off-by: Rob White <rob@blue-wave.net>