Multi manifest build - arm64/arm (new) + amd64 (current)

[YOU54F]

closes #51

create and publish arm64 + arm versions of pact cli and pact broker docker images for use in raspberry Pi's / mac m1/2 etc.

currently publishing to personal docker hub acc for testing

• https://hub.docker.com/r/you54f/pact-cli

Related

• https://github.com/pact-foundation/pact-broker-docker/issues/30
• https://hub.docker.com/r/you54f/pact-broker
• https://github.com/pact-foundation/pact-broker-docker/pull/123

Have spun up the images briefly on an m1 pro macbook but would warrant some decent testing - I have several pi's (3b+ and 4) so will give them a whirl