update required C++ standard

[KristofferC]

[codecov[bot]]

Codecov Report

Merging #638 (02c1765) into master (981a550) will not change coverage. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #638   +/-   ##
=======================================
  Coverage   95.41%   95.41%           
=======================================
  Files           2        2           
  Lines         458      458           
=======================================
  Hits          437      437           
  Misses         21       21           

Impacted Files	Coverage Δ
src/juliaconfig.jl	90.69% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 981a550...02c1765. Read the comment docs.