Enable error level for the InvalidInlineTag bug pattern in ErrorProne

Issues with this bug pattern have already been fixed by change
Id068891ef, but that change accidentally set the bug pattern to WARN
instead of ERROR.

Bug: Issue 15067
Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I8fe2d90527876fff33a2f7203a49d837a3bccbea
diff --git a/tools/BUILD b/tools/BUILD
index e44ae78..f952c63 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -241,7 +241,7 @@
         "-Xep:InstantTemporalUnit:ERROR",
         "-Xep:IntLongMath:ERROR",
         # "-Xep:InvalidBlockTag:WARN",
-        "-Xep:InvalidInlineTag:WARN",
+        "-Xep:InvalidInlineTag:ERROR",
         "-Xep:InvalidJavaTimeConstant:ERROR",
         "-Xep:InvalidLink:ERROR",
         # "-Xep:InvalidParam:WARN",