update RELEASE version number

Author: cying111

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: bambu
 Type: Package
 Title: Context-Aware Transcript Quantification from Long Read RNA-Seq data
-Version: 3.13.1
+Version: 3.12.1
 Authors@R: c(person("Ying", "Chen", role = c("cre","aut"),
              email = "[email protected]"),
              person("Andre", "Sim", role = "aut",