Update antlr4, antlr4-runtime to 4.9.2 (#2137)

Co-authored-by: Jiuyang Liu <liu@jiuyang.me>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/build.sbt b/build.sbt
index 3e5f591b..7945f512 100644
--- a/build.sbt
+++ b/build.sbt
@@ -93,7 +93,7 @@ lazy val antlrSettings = Seq(
   antlr4GenVisitor in Antlr4 := true,
   antlr4GenListener in Antlr4 := false,
   antlr4PackageName in Antlr4 := Option("firrtl.antlr"),
-  antlr4Version in Antlr4 := "4.8",
+  antlr4Version in Antlr4 := "4.9.2",
   javaSource in Antlr4 := (sourceManaged in Compile).value
 )
 
diff --git a/build.sc b/build.sc
index 90daeb22..19a78069 100644
--- a/build.sc
+++ b/build.sc
@@ -90,7 +90,7 @@ class firrtlCrossModule(val crossScalaVersion: String) extends CrossSbtModule wi
   }
 
   /* antlr4 */
-  def antlr4Version = "4.8"
+  def antlr4Version = "4.9.2"
 
   def antlrSource = T.source {
     millSourcePath / "src" / "main" / "antlr4" / "FIRRTL.g4"