[Buildroot] [PATCH 1/1 v2] package/boost: bump to version 1.74.0

[Michael Nosthoff]

On 09.09.2020 11:32, Maxim Kochetkov via buildroot wrote:
> gcc 10 C++20 breaks boost library due to allocator changes.
> https://github.com/boostorg/bimap/issues/23
>
> We need boost 1.74.0 to fix build with gcc 10
>
> Signed-off-by: Maxim Kochetkov <fido_max at inbox.ru>

Reviewed-by: Michael Nosthoff <buildroot at heine.tech>
Tested-by: Michael Nosthoff <buildroot at heine.tech>  for arm
cortex-a15/gcc9/glibc