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/sigs.k8s.io/json/README.md

@@ -0,0 +1,40 @@
+# sigs.k8s.io/json
+
+[![Go Reference](https://pkg.go.dev/badge/sigs.k8s.io/json.svg)](https://pkg.go.dev/sigs.k8s.io/json)
+
+## Introduction
+
+This library is a subproject of [sig-api-machinery](https://github.com/kubernetes/community/tree/master/sig-api-machinery#json).
+It provides case-sensitive, integer-preserving JSON unmarshaling functions based on `encoding/json` `Unmarshal()`.
+
+## Compatibility
+
+The `UnmarshalCaseSensitivePreserveInts()` function behaves like `encoding/json#Unmarshal()` with the following differences:
+
+- JSON object keys are treated case-sensitively.
+  Object keys must exactly match json tag names (for tagged struct fields)
+  or struct field names (for untagged struct fields).
+- JSON integers are unmarshaled into `interface{}` fields as an `int64` instead of a 
+  `float64` when possible, falling back to `float64` on any parse or overflow error.
+- Syntax errors do not return an `encoding/json` `*SyntaxError` error.
+  Instead, they return an error which can be passed to `SyntaxErrorOffset()` to obtain an offset.
+
+## Additional capabilities
+
+The `UnmarshalStrict()` function decodes identically to `UnmarshalCaseSensitivePreserveInts()`,
+and also returns non-fatal strict errors encountered while decoding:
+
+- Duplicate fields encountered
+- Unknown fields encountered
+
+### Community, discussion, contribution, and support
+
+You can reach the maintainers of this project via the 
+[sig-api-machinery mailing list / channels](https://github.com/kubernetes/community/tree/master/sig-api-machinery#contact).
+
+### Code of conduct
+
+Participation in the Kubernetes community is governed by the [Kubernetes Code of Conduct](code-of-conduct.md).
+
+[owners]: https://git.k8s.io/community/contributors/guide/owners.md
+[Creative Commons 4.0]: https://git.k8s.io/website/LICENSE