Bump `clang` version to 11 and install `libboost-dev`

[ismaelsadeeq]

Thank you @fanquake for this scripts.

I was having issues running the fuzzing commands

./configure --prefix=/bitcoin/depends/x86_64-pc-linux-gnu \
    --enable-fuzz --with-sanitizers=fuzzer,address,undefined \
    CC=clang-9 CXX=clang++-9

emits the following error

checking dependency style of clang++-9... gcc3
checking whether clang++-9 supports C++20 features with -std=c++20... no
checking whether clang++-9 supports C++20 features with +std=c++20... no
checking whether clang++-9 supports C++20 features with -h std=c++20... no
configure: error: *** A compiler with support for C++20 language features is required.

commands below Fixed the error

apt install clang
./configure --prefix=/bitcoin/depends/x86_64-pc-linux-gnu \
    --enable-fuzz --with-sanitizers=fuzzer,address,undefined \
    CC=clang-11 CXX=clang++-11

So bump to clang 11 and also require installing libboost-dev its also a dependency

[fanquake]

Thanks. Note that this needed a number of other changes, so I've pushed them all in https://github.com/fanquake/core-review/commit/7ebe56772420662217f6fd59e8f46aea145b4a76, and added you as co-author.

Boost-devel wasn't needed, as this build is using depends, and I picked clang-15 over clang-11.

[ismaelsadeeq]

Thanks for the update.