chore(deps): bump golang from `5d2b868` to `5f68ec6` in /e2e (#6471)

Bumps golang from `5d2b868` to `5f68ec6`.

---
updated-dependencies:
- dependency-name: golang
  dependency-version: 1.26.4-bookworm
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

e2e/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.26.4-bookworm@sha256:5d2b868674b57c9e48cdd39e891acce4196b6926ca6d11e9c270a8f85106203d AS builder
+FROM golang:1.26.4-bookworm@sha256:5f68ec6805843bd3981a951ffada82a26a0bd2631045c8f7dba483fa868f5ec5 AS builder
 RUN go install github.com/onsi/ginkgo/v2/ginkgo@v2.1.6
 
 FROM alpine:3.23.4@sha256:5b10f432ef3da1b8d4c7eb6c487f2f5a8f096bc91145e68878dd4a5019afde11