Ignore errors in memoizedGetDependencies

Dependencies are required to find URLs. If getting dependecies fails, it
should not prevent Scala Steward from creating the PR.

This is another source of errors which will be eliminated with #851.

Author: fthomas

modules/core/src/main/scala/org/scalasteward/core/nurture/NurtureAlg.scala

@@ -78,7 +78,9 @@ final class NurtureAlg[F[_]](
       grouped = Update.group(filtered)
       _ <- logger.info(util.logger.showUpdates(grouped))
       baseSha1 <- gitAlg.latestSha1(repo, baseBranch)
-      memoizedGetDependencies <- Async.memoize(sbtAlg.getDependencies(repo))
+      memoizedGetDependencies <- Async.memoize {
+        sbtAlg.getDependencies(repo).handleError(_ => List.empty)
+      }
       _ <- grouped.traverse_ { update =>
         val data =
           UpdateData(