Fix IndexStyle depwarn on 0.6

[timholy]

No description provided.

[codecov-io]

Codecov Report

Merging #7 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master     #7   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           1      1           
  Lines          15     15           
=====================================
  Hits           15     15

Impacted Files	Coverage Δ
src/IndirectArrays.jl	100% <100%> (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 02feb5b...9567565. Read the comment docs.