Bump antlr4 from 4.5.3 to 4.9.3 in /modules/lang-painless (#2537)

Bumps [antlr4](https://github.com/antlr/antlr4) from 4.5.3 to 4.9.3.
- [Release notes](https://github.com/antlr/antlr4/releases)
- [Changelog](https://github.com/antlr/antlr4/blob/master/CHANGES.txt)
- [Commits](https://github.com/antlr/antlr4/compare/4.5.3...4.9.3)

---
updated-dependencies:
- dependency-name: org.antlr:antlr4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

modules/lang-painless/build.gradle

@@ -45,7 +45,7 @@ testClusters.all {
 }
 
 dependencies {
-  api 'org.antlr:antlr4-runtime:4.5.3'
+  api 'org.antlr:antlr4-runtime:4.9.3'
   api 'org.ow2.asm:asm-util:9.2'
   api 'org.ow2.asm:asm-tree:7.2'
   api 'org.ow2.asm:asm-commons:9.2'

modules/lang-painless/licenses/antlr4-runtime-4.5.3.jar.sha1

@@ -1 +0,0 @@
-2609e36f18f7e8d593cc1cddfb2ac776dc96b8e0

modules/lang-painless/licenses/antlr4-runtime-4.9.3.jar.sha1

@@ -0,0 +1 @@
+81befc16ebedb8b8aea3e4c0835dd5ca7e8523a8