Update library dependencies

[duttonw]

Issues found and libraries updated to latest versions:
guava-18.0: CVE-2018-10237
jackson-databind-2.9.8: CVE-2019-12086

Fixes issue #451

Contributing to Twilio

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[childish-sambino]

Build is failing because guava 23 was the last version to support Java 7, unless switching to the -android variant.

[duttonw]

https://github.com/google/guava/wiki/CVE-2018-10237

Unbounded memory allocation in Google Guava 11.0 through 24.1

Nice to get to 23 but still in the cve range.

Java 7 is now EOL for the public since 2015 (2022? for people still paying and is still supported in Spring Framework 4.3.x until June 2020)
https://en.wikipedia.org/wiki/Java_version_history#cite_note-ReferenceC-163

[thinkingserious]

Thank you for the PR @duttonw!

[duttonw]

Have ignored CVE-2019-12814 due to no release being out to fix this yet. Have included comments as what we are waiting on in the ignore owasp file.

[duttonw]

Having to think outside the box to get the owasp checker to run on all versions of Java except 1.7 was interesting.