Bump com.github.jnr:jnr-ffi from 2.2.17 to 2.2.18 in /log4j-cassandra (#3971)

Bumps [com.github.jnr:jnr-ffi](https://github.com/jnr/jnr-ffi) from 2.2.17 to 2.2.18.
- [Commits](jnr/jnr-ffi@jnr-ffi-2.2.17...jnr-ffi-2.2.18)

---
updated-dependencies:
- dependency-name: com.github.jnr:jnr-ffi
  dependency-version: 2.2.18
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

log4j-cassandra/pom.xml

@@ -46,7 +46,7 @@
     <!-- at least this version has one CVE less than the one suggested by Cassandra -->
     <guava.version>25.1-jre</guava.version>
     <!-- Pinned transitive dependencies for reproducibility between Linux and MacOS -->
-    <jnr-ffi.version>2.2.17</jnr-ffi.version>
+    <jnr-ffi.version>2.2.18</jnr-ffi.version>
     <snappy.version>1.1.10.8</snappy.version>
   </properties>