Add ARM64 job in Travis-CI

[odidev]

Patch Details: Following files has been modified :
travis.yml: Added arm64 architecture in travis.yml
tools/verify-all.sh: Modified verify-all.sh file by updating the version of docker image for package openapi-generator-cli which is supported on arm64 platform

Signed-off-by: odidev odidev@puresoftware.com

[linux-foundation-easycla]

• ❌ login: @odidev / The commit (415fb8a). This user is authorized, but they must confirm their affiliation with their company. Start the authorization process by clicking here, click "Corporate", select the appropriate company from the list, then confirm your affiliation on the page that appears. For further assistance with EasyCLA, please submit a support request ticket.

[timscharfenort8]

good