ZOOKEEPER-4827 Bump bouncycastl version from 1.75 to 1.78 (#2158)

Signed-off-by: ZhangJian He <shoothzj@gmail.com>

pom.xml

@@ -565,7 +565,7 @@
     <jline.version>2.14.6</jline.version>
     <snappy.version>1.1.10.5</snappy.version>
     <kerby.version>2.0.0</kerby.version>
-    <bouncycastle.version>1.75</bouncycastle.version>
+    <bouncycastle.version>1.78</bouncycastle.version>
     <commons-collections.version>4.4</commons-collections.version>
     <dropwizard.version>4.1.12.1</dropwizard.version>
     <spotbugsannotations.version>4.0.2</spotbugsannotations.version>