build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/google.golang.org/grpc/CONTRIBUTING.md

@@ -0,0 +1,73 @@
+# How to contribute
+
+We definitely welcome your patches and contributions to gRPC! Please read the gRPC
+organization's [governance rules](https://github.com/grpc/grpc-community/blob/master/governance.md)
+and [contribution guidelines](https://github.com/grpc/grpc-community/blob/master/CONTRIBUTING.md) before proceeding.
+
+If you are new to GitHub, please start by reading [Pull Request howto](https://help.github.com/articles/about-pull-requests/)
+
+## Legal requirements
+
+In order to protect both you and ourselves, you will need to sign the
+[Contributor License Agreement](https://identity.linuxfoundation.org/projects/cncf).
+
+## Guidelines for Pull Requests
+How to get your contributions merged smoothly and quickly.
+
+- Create **small PRs** that are narrowly focused on **addressing a single
+  concern**. We often times receive PRs that are trying to fix several things at
+  a time, but only one fix is considered acceptable, nothing gets merged and
+  both author's & review's time is wasted. Create more PRs to address different
+  concerns and everyone will be happy.
+
+- If you are searching for features to work on, issues labeled [Status: Help
+  Wanted](https://github.com/grpc/grpc-go/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3A%22Status%3A+Help+Wanted%22)
+  is a great place to start. These issues are well-documented and usually can be
+  resolved with a single pull request.
+
+- If you are adding a new file, make sure it has the copyright message template
+  at the top as a comment. You can copy over the message from an existing file
+  and update the year.
+
+- The grpc package should only depend on standard Go packages and a small number
+  of exceptions. If your contribution introduces new dependencies which are NOT
+  in the [list](https://godoc.org/google.golang.org/grpc?imports), you need a
+  discussion with gRPC-Go authors and consultants.
+
+- For speculative changes, consider opening an issue and discussing it first. If
+  you are suggesting a behavioral or API change, consider starting with a [gRFC
+  proposal](https://github.com/grpc/proposal).
+
+- Provide a good **PR description** as a record of **what** change is being made
+  and **why** it was made. Link to a GitHub issue if it exists.
+
+- If you want to fix formatting or style, consider whether your changes are an
+  obvious improvement or might be considered a personal preference. If a style
+  change is based on preference, it likely will not be accepted. If it corrects
+  widely agreed-upon anti-patterns, then please do create a PR and explain the
+  benefits of the change.
+
+- Unless your PR is trivial, you should expect there will be reviewer comments
+  that you'll need to address before merging. We'll mark it as `Status: Requires
+  Reporter Clarification` if we expect you to respond to these comments in a
+  timely manner. If the PR remains inactive for 6 days, it will be marked as
+  `stale` and automatically close 7 days after that if we don't hear back from
+  you.
+
+- Maintain **clean commit history** and use **meaningful commit messages**. PRs
+  with messy commit history are difficult to review and won't be merged. Use
+  `rebase -i upstream/master` to curate your commit history and/or to bring in
+  latest changes from master (but avoid rebasing in the middle of a code
+  review).
+
+- Keep your PR up to date with upstream/master (if there are merge conflicts, we
+  can't really merge your change).
+
+- **All tests need to be passing** before your change can be merged. We
+  recommend you **run tests locally** before creating your PR to catch breakages
+  early on.
+  - `./scripts/vet.sh` to catch vet errors
+  - `go test -cpu 1,4 -timeout 7m ./...` to run the tests
+  - `go test -race -cpu 1,4 -timeout 7m ./...` to run tests in race mode
+
+- Exceptions to the rules can be made if there's a compelling reason for doing so.