repair build toolchain

Author: christophfink

build.gradle

@@ -50,7 +50,7 @@ publishing {
     repositories {
         maven {
             name = "GitHubPackages"
-            url = uri("https://maven.pkg.github.com/conveyal/r5")
+            url = uri("https://maven.pkg.github.com/"  + System.getenv("GITHUB_PACKAGE_REPOSITORY"))
             credentials {
                 username = System.getenv("GITHUB_ACTOR")
                 password = System.getenv("GITHUB_TOKEN")