Update io_bazel_rules_scala digest to 3921c50

Author: renovate[bot]

WORKSPACE

@@ -58,9 +58,9 @@ http_archive(
 
 http_archive(
     name = "io_bazel_rules_scala",
-    sha256 = "31dac610fe73d7211ea2083540d085a8f8b582ac8afc3f449173309eda7fc7df",
-    strip_prefix = "rules_scala-b17e9e0580ba28f95559676dd88cd99ec4f08195",
-    url = "https://github.com/bazelbuild/rules_scala/archive/b17e9e0580ba28f95559676dd88cd99ec4f08195.tar.gz",
+    sha256 = "c511430c23ed5ecf48a922d2e2210497e7f0127da5e286f2c94e67d9b9498192",
+    strip_prefix = "rules_scala-3921c504ca8a9efbf18f3bd50b5e9e855b7317ab",
+    url = "https://github.com/bazelbuild/rules_scala/archive/3921c504ca8a9efbf18f3bd50b5e9e855b7317ab.tar.gz",
 )
 
 http_archive(