CompatHelper: bump compat for IntervalSets to 0.7, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the IntervalSets package from 0.5.1 to 0.5.1, 0.7.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov]

Codecov Report

Merging #57 (54b6e8d) into master (801034e) will decrease coverage by 0.24%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #57      +/-   ##
==========================================
- Coverage   65.23%   64.99%   -0.25%     
==========================================
  Files          22       22              
  Lines        1562     1551      -11     
==========================================
- Hits         1019     1008      -11     
  Misses        543      543              

Impacted Files	Coverage Δ
src/fd_derivatives.jl	48.28% <0.00%> (-0.59%)	⬇️
src/bsplines.jl	76.08% <0.00%> (-0.51%)	⬇️
src/knot_sets.jl	72.94% <0.00%> (-0.32%)	⬇️
src/finite_differences.jl	70.31% <0.00%> (-0.31%)	⬇️
src/linear_operators.jl	81.25% <0.00%> (-0.29%)	⬇️
src/fedvr.jl	87.03% <0.00%> (-0.06%)	⬇️

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