Fix error prone warnings

The recent java toolchain and error prone upgrades brought new warnings
to the plugin and here is a fix.

The following warning gets fixed:
  [FloggerLogString] Arguments to log(String) must be compile-time
  constants or parameters annotated with @CompileTimeConstant.
  If possible, use Flogger's formatting log methods instead.

Change-Id: I4737a8b735e8923b4211c4df00ecf6fab0715e2e
diff --git a/owners/src/main/java/com/googlesource/gerrit/owners/OwnersSubmitRequirement.java b/owners/src/main/java/com/googlesource/gerrit/owners/OwnersSubmitRequirement.java
index c6af4c8..a0339de 100644
--- a/owners/src/main/java/com/googlesource/gerrit/owners/OwnersSubmitRequirement.java
+++ b/owners/src/main/java/com/googlesource/gerrit/owners/OwnersSubmitRequirement.java
@@ -167,14 +167,14 @@
           String.format(
               "Project '%s': repository cannot be opened to evaluate OWNERS submit requirements.",
               project);
-      logger.atSevere().withCause(e).log(msg);
+      logger.atSevere().withCause(e).log("%s", msg);
       throw new IllegalStateException(msg, e);
     } catch (DiffNotAvailableException e) {
       String msg =
           String.format(
               "Project '%s' change #%d: unable to get diff to evaluate OWNERS submit requirements.",
               project, changeId);
-      logger.atSevere().withCause(e).log(msg);
+      logger.atSevere().withCause(e).log("%s", msg);
       throw new IllegalStateException(msg, e);
     }
   }