Upgrade to Httpclient 4.5.12

Closes gh-20645

Author: snicoll

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -78,7 +78,7 @@
 		<hsqldb.version>2.5.0</hsqldb.version>
 		<htmlunit.version>2.36.0</htmlunit.version>
 		<httpasyncclient.version>4.1.4</httpasyncclient.version>
-		<httpclient.version>4.5.11</httpclient.version>
+		<httpclient.version>4.5.12</httpclient.version>
 		<httpcore.version>4.4.13</httpcore.version>
 		<infinispan.version>9.4.18.Final</infinispan.version>
 		<influxdb-java.version>2.15</influxdb-java.version>