Upgrade image version + update readme

Merge pull request #22 from uswitch/air-4707/patch-synk-vulnerabilities

Patch snyk agent vulnerabilities v0.8.13-1 -> v1.34.0

GHA migration and minor fixes v0.8.13-1

Merge pull request #18 from uswitch/upstream-dns-url-fix

fix upstream dns url

Merge pull request #17 from uswitch/fix-image

AIRSHIP-2454 Replace k8s.gcr.io with registry.k8s.io

Merge pull request #16 from uswitch/node-local-dns-test

change node-local-dns test from using chaos class

Merge pull request #15 from uswitch/upgrade-v0.8.12

Update docker image to be based on v0.8.12