We've just made the main branch as the default one.

Workflow for backend was broken because in a latest update on github
set-env and add-path commands were deprecated and will no longer be
allowed and the version of actions/setup-go we uses these commands.

Thus this patch updates the version of go as well as specifies the
correct version for actions/setup-go.

New version of Go and actions@checkout are available. Add action to run
for changes in .github directory and on push to master branch event.
Signed-off-by: knrt10 <tripathi.kautilya@gmail.com>

These changes add the github actions that represent the CI system for
now.