fix(package-json): invalid webpack commit sha hyperledger-cacti#506

This commit is necessary because of a rebase that
happened on the fork where the webpack feature we
need was implemented. The rebase changed the commit
sha and therefore made that version of the code
disappear too. To avoid this issue happening again
in the future a dedicated branch was created on the
fork which will not be touched by future rebases
that are necessary for the pull request to be kept
up to date with the main branch of webpack itself.

The so called backup branch mentioned above is called
cactus-webpack-ignore-require-calls-feature which
you can see being specified in the package.json.

Fixes hyperledger-cacti#506

Signed-off-by: Peter Somogyvari <peter.somogyvari@accenture.com>