Bump version to v0.6.21

[jishnub]

No description provided.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.67 🎉

Comparison is base (ee2cf8f) 68.42% compared to head (2fca161) 69.10%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #225      +/-   ##
==========================================
+ Coverage   68.42%   69.10%   +0.67%     
==========================================
  Files          28       28              
  Lines        2521     2570      +49     
==========================================
+ Hits         1725     1776      +51     
+ Misses        796      794       -2     

Impacted Files	Coverage Δ
src/Spaces/Ultraspherical/Ultraspherical.jl	91.07% <ø> (ø)
src/ApproxFunOrthogonalPolynomials.jl	81.48% <100.00%> (+37.03%)	⬆️
src/Spaces/IntervalSpace.jl	83.33% <100.00%> (+8.33%)	⬆️
src/Spaces/Jacobi/Jacobi.jl	65.34% <100.00%> (+0.34%)	⬆️
src/Spaces/Jacobi/JacobiOperators.jl	83.68% <100.00%> (+0.69%)	⬆️
src/Spaces/Laguerre/Laguerre.jl	60.13% <100.00%> (ø)
...c/Spaces/Ultraspherical/UltrasphericalOperators.jl	81.14% <100.00%> (+1.81%)	⬆️
src/fastops.jl	100.00% <100.00%> (ø)
src/roots.jl	74.56% <100.00%> (+0.92%)	⬆️
src/show.jl	60.52% <100.00%> (+4.64%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.