Update README

[Lecrapouille]

• Hello ! First line:

A header only c++ library that provides type safety

Could be nice to explicitly say it is C++17 directly on the 1st line (else said on section "building & compat" which is far away).

• The illustrative example does not compile (g++ --std=c++17 foo.cpp). I git cloned the HEAD:

  foo.cpp:9:46: error: ‘const struct SI::detail::unit_t<'M', std::ratio<1>, long double, std::ratio<1> >’ has no member named ‘as’
  9 | constexpr auto thousand_grams = one_kilogram.as<SI::gram_t>();
    |                                              ^~
  foo.cpp:9:59: error: missing template arguments before ‘>’ token
  9 | constexpr auto thousand_grams = one_kilogram.as<SI::gram_t>();
    |                                                           ^
  foo.cpp:9:61: error: expected primary-expression before ‘)’ token
  9 | constexpr auto thousand_grams = one_kilogram.as<SI::gram_t>();
    |  

[bernedom]

You're right the examples does no longer compile since release 2.5.0 which removed some implicit conversions.

At the moment the correct code would be constexpr auto thousand_grams = one_kilogram.as<SI::gram_t<long double>>();

which is not that nice. Will try to fix it

[bernedom]

The issue is fixed in this branch https://github.com/bernedom/SI/tree/feature/add-tests-for-as-conversion which will go in the next release.

[bernedom]

Released with version 2.5.1.