Update to CNI & Plugins 1.0.1 with stable 1.0 spec

[dtrudg]

Description of the Pull Request (PR):

Update to CNI & Plugins 1.0.1 with stable 1.0 spec

The flannel plugin is now part of a different repository, so is not
built as part of a singularityce install.

Plugins sbr and vrf that were previously not built, but are part
of plugins v1.0.1, have been added to the build.

This fixes or addresses the following GitHub issues:

• Fixes Update CNI plugins to v1.0.1 #336

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• Read the Guidelines for Contributing, and this PR conforms to the stated requirements.
• Added changes to the CHANGELOG if necessary according to the Contribution Guidelines
• Added tests to validate this PR, linted with make check and tested this PR locally with a make test, and make testall if possible (see CONTRIBUTING.md).
• Based this PR against the appropriate branch according to the Contribution Guidelines
• Added myself as a contributor to the Contributors File

[dtrudg]

Test is failing.

The assumption for CNI_ARGS passed to plugins is that a plugin that consumes any arg must consume all args, or it's an error. (containernetworking/cni#560).

Before updating to 1.0.1 the bridge plugin consumed no args, so the fact that we were passing IP= didn't matter. As the bridge plugin now consumes a CNI_ARG (containernetworking/plugins#636) we now get an error because it doesn't consume IP=

Exact situation predicted in containernetworking/cni#560....

In addition, not only in chained case, similar case could be happen when both IPAM and interface CNI (e.g. bridge) consume CNI_ARGS in the future, hence I suppose we could just remove the check.

[dtrudg]

Forgot to update the example config version to 1.0.0... now done.