Change minimum supported Julia to 1.5

Author: BioTurboNick

Project.toml

@@ -22,7 +22,7 @@ IrrationalConstants = "0.1, 0.2"
 LogExpFunctions = "0.3.2"
 OpenLibm_jll = "0.7, 0.8"
 OpenSpecFun_jll = "0.5"
-julia = "1.3"
+julia = "1.5"
 
 [extras]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"