Fix bomr version range constraint for single version

This commit fixes the version range in our DSL to use brackets around
a particular version we have to skip.

See https://maven.apache.org/enforcer/enforcer-rules/versionRanges.html

Closes gh-36976

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -59,7 +59,7 @@ bom {
 	}
 	library("ANTLR2", "2.7.7") {
 		prohibit {
-			versionRange "20030911"
+			versionRange "[20030911]"
 			because "it is old version that used a different versioning scheme"
 		}
 		group("antlr") {
@@ -1502,7 +1502,7 @@ bom {
 	}
 	library("RSocket", "1.1.3") {
 		prohibit {
-			versionRange "1.1.4"
+			versionRange "[1.1.4]"
 			because "it contains a regression (https://github.com/rsocket/rsocket-java/issues/1092)"
 		}
 		group("io.rsocket") {