CompatHelper: bump compat for ApproxFunBase to 0.8, (keep existing compat) (#863)

* CompatHelper: bump compat for ApproxFunBase to 0.8, (keep existing compat)

* bump version to v0.13.15

---------

Co-authored-by: CompatHelper Julia <compathelper_noreply@julialang.org>
Co-authored-by: Jishnu Bhattacharya <jishnub.github@gmail.com>

Author: 3 people

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFun"
 uuid = "28f2ccd6-bb30-5033-b560-165f7b14dc2f"
-version = "0.13.14"
+version = "0.13.15"
 
 [deps]
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"
@@ -22,7 +22,7 @@ StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
 [compat]
 AbstractFFTs = "1.0"
-ApproxFunBase = "0.7.34"
+ApproxFunBase = "0.7.34, 0.8"
 ApproxFunBaseTest = "0.1"
 ApproxFunFourier = "0.3"
 ApproxFunOrthogonalPolynomials = "0.5, 0.6"