Dependency update

Updates the Paho client dependency to version 1.2.4 and Jackson to 2.12.6.1.
Also updates README documentation.

What's Changed

• Give explicit permissions to Github actions by @graebm in #184
• Jackson bump by @bretambrose in #185
• Update Paho to latest version by @TwistedTwigleg in #186

New Contributors

• @graebm made their first contribution in #184
• @TwistedTwigleg made their first contribution in #186

Full Changelog: v1.3.10...v1.3.11