Update Bouncy Castle to 1.59

- pick up CVE fixes, etc.
  https://www.bouncycastle.org/latest_releases.html

Change-Id: Iced880a43cd5250a4fa5af32528f43ed29a5ed6f
diff --git a/lib/pom.xml b/lib/pom.xml
index 581e2d3..8ae2c4d 100644
--- a/lib/pom.xml
+++ b/lib/pom.xml
@@ -53,7 +53,7 @@
         <slf4j.version>1.7.21</slf4j.version>
         <guava.version>22.0</guava.version>
         <commons.io.version>2.6</commons.io.version>
-        <bouncycastle.version>1.58</bouncycastle.version>
+        <bouncycastle.version>1.59</bouncycastle.version>
         <!-- TODO argLine was originally added maven-surfire-plugin configuration
                   to fix locale errors for non-US developers. However, it breaks
                   SonarQube's test coverage, so moving here for now. -->