use method.degree instead of constructing a new one

[johnnychen94]

Unfortunately, the previous compat patch doesn't work very well in Interpolations v0.13.3 JuliaMath/Interpolations.jl#442

This PR directly uses method.degree so as to avoid the construction of it.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@c66b77a). Click here to learn what that means.
The diff coverage is 91.36%.

@@            Coverage Diff            @@
##             master     #132   +/-   ##
=========================================
  Coverage          ?   92.09%           
=========================================
  Files             ?        8           
  Lines             ?      215           
  Branches          ?        0           
=========================================
  Hits              ?      198           
  Misses            ?       17           
  Partials          ?        0           

Impacted Files	Coverage Δ
src/warpedview.jl	85.71% <75.00%> (ø)
src/ImageTransformations.jl	83.33% <80.00%> (ø)
src/compat.jl	83.33% <83.33%> (ø)
src/interpolations.jl	72.00% <85.71%> (ø)
src/autorange.jl	91.83% <90.62%> (ø)
src/invwarpedview.jl	97.14% <93.33%> (ø)
src/resizing.jl	100.00% <100.00%> (ø)
src/warp.jl	100.00% <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 c66b77a...3578eb4. Read the comment docs.