CompatHelper: bump compat for Interpolations to 0.15, (keep existing compat) (#78)

Co-authored-by: CompatHelper Julia <compathelper_noreply@julialang.org>

Author: github-actions[bot]

Project.toml

@@ -45,7 +45,7 @@ EchelleCCFs = "0.2"
 EchelleInstruments = "0.2"
 FITSIO = "0.16, 0.17"
 FileIO = "1.4"
-Interpolations = "0.12, 0.13, 0.14"
+Interpolations = "0.12, 0.13, 0.14, 0.15"
 JLD2 = "0.2, 0.3, 0.4"
 KernelFunctions = "0.9.7, 0.10"
 LsqFit = "0.11, 0.12, 0.13, 0.15"