chore(deps): Update dependency net.fabricmc:fabric-loader to v0.15.6

Author: renovate[bot]

gradle/libs.versions.toml

@@ -23,7 +23,7 @@ paperApi = "1.16.5-R0.1-SNAPSHOT"
 paperlib = "1.0.8"
 waterfallApi = "1.16-R0.5-SNAPSHOT"
 fabricApi = "0.93.1+1.20.4"
-fabricLoader = "0.15.3"
+fabricLoader = "0.15.6"
 minecraft = "1.20.4"
 spongeApi7 = "7.2.0"
 velocityApi = "3.2.0-SNAPSHOT"