Update to GAP 4.15.0 (#1244)

Author: lgoettgens

.github/workflows/CI-distro.yml

@@ -75,6 +75,7 @@ jobs:
           - gap-package: 'polymaking'                 # `polymake command not found. Please set POLYMAKE_COMMAND by hand`
           - gap-package: 'profiling'                  # segfaults during testing
           - gap-package: 'ringsforhomalg'             # `Error, found no GAP executable in PATH`
+          - gap-package: 'smallclassnr'               # tests pass, but the job fails. Needs to be investigated further
           - gap-package: 'toricvarieties'             # random segfaults during testing
           - gap-package: 'xgap'                       # no jll
 

.github/workflows/GAP_patches/stable-4.14/Add-packagedirs-and-ExtendPackageDirectories-5873.patch

@@ -30,7 +30,7 @@ jobs:
       matrix:
         gap-version:
           - 'master'
-          - 'stable-4.14'
+          - 'stable-4.15'
         julia-version:
           - '1'         # latest stable release
           - '1.12-nightly'
@@ -42,7 +42,7 @@ jobs:
           - gap-version: 'master'
             julia-version: '1'
             os: macOS-latest
-          - gap-version: 'stable-4.14'
+          - gap-version: 'stable-4.15'
             julia-version: '1'
             os: macOS-latest