Update swipl to 8.1.15

library/swipl

@@ -1,10 +1,10 @@
 Maintainers: Dave Curylo <[email protected]> (@ninjarobot)
 GitRepo: https://github.com/SWI-Prolog/docker-swipl.git
-GitCommit: 87ae5e3e6e67594f835dfb34ffa2c57d7ed65ce1
+GitCommit: 7fc2e1a7f5e48a72769b15991413432542cc7caf
 
-Tags: latest, 8.1.12
+Tags: latest, 8.1.15
 Architectures: amd64, arm32v7, arm64v8
-Directory: 8.1.12/stretch
+Directory: 8.1.15/stretch
 
 Tags: stable, 8.0.3
 Directory: 8.0.3/stretch