Update Bouncy Castle (#6361)

Note: these are test dependencies. Updated the artifacts to
`bcpkix-jdk18on` (compatible with Java 1.8 and onwards) since
`bcpkix-jdk15on` hasn't been updated since 2021 and still on 1.70. This
change is okay because these are test dependencies and the SDK is
baselined on Java 8.

Author: dagnir

test/http-client-tests/pom.xml

@@ -120,8 +120,8 @@
         </dependency>
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcpkix-jdk15on</artifactId>
-            <version>1.70</version>
+            <artifactId>bcpkix-jdk18on</artifactId>
+            <version>1.80</version>
             <scope>compile</scope>
         </dependency>
         <dependency>

test/protocol-tests/pom.xml

@@ -292,8 +292,8 @@
         </dependency>
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcpkix-jdk15on</artifactId>
-            <version>1.70</version>
+            <artifactId>bcpkix-jdk18on</artifactId>
+            <version>1.80</version>
             <scope>test</scope>
         </dependency>
         <dependency>