Bump antlr4 from 4.9 to 4.9.1

Bumps [antlr4](https://github.com/antlr/antlr4) from 4.9 to 4.9.1.
- [Release notes](https://github.com/antlr/antlr4/releases)
- [Changelog](https://github.com/antlr/antlr4/blob/master/CHANGES.txt)
- [Commits](antlr/antlr4@4.9...4.9.1)

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -123,7 +123,7 @@ dependencies {
     antlr3 'org.antlr:antlr:3.5.2'
     implementation 'org.antlr:antlr-runtime:3.5.2'
 
-    antlr4 'org.antlr:antlr4:4.9'
+    antlr4 'org.antlr:antlr4:4.9.1'
     implementation 'org.antlr:antlr4-runtime:4.9.1'
 
     implementation (group: 'org.apache.lucene', name: 'lucene-queryparser', version: '8.7.0') {