sig-release: Remove the deprecated hyperkube subproject from listing

Signed-off-by: Stephen Augustus <foo@auggie.dev>

sig-release/README.md

@@ -82,11 +82,6 @@ The Kubernetes Release Team is responsible for the day-to-day work required to s
 Documents and processes related to SIG Release
 - **Owners:**
   - [kubernetes/sig-release](https://github.com/kubernetes/sig-release/blob/master/OWNERS)
-### hyperkube
-Best-effort maintaining of hyperkube until 1.18 goes EOL 2021-04-30.
-- **Owners:**
-  - [kubernetes/kubernetes/cluster/images/hyperkube](https://github.com/kubernetes/kubernetes/blob/release-1.18/cluster/images/hyperkube/OWNERS)
-  - [kubernetes/release/images/build/debian-hyperkube-base](https://github.com/kubernetes/release/blob/master/images/build/debian-hyperkube-base/OWNERS)
 ### kubernetes/repo-infra
 Creates and maintains tools and templates for Kubernetes org repositories.
 Includes bazel tooling for managing dependencies for kubernetes/kubernetes

sigs.yaml

@@ -1941,12 +1941,6 @@ sigs:
       Documents and processes related to SIG Release
     owners:
     - https://raw.githubusercontent.com/kubernetes/sig-release/master/OWNERS
-  - name: hyperkube
-    description: |
-      Best-effort maintaining of hyperkube until 1.18 goes EOL 2021-04-30.
-    owners:
-    - https://raw.githubusercontent.com/kubernetes/kubernetes/release-1.18/cluster/images/hyperkube/OWNERS
-    - https://raw.githubusercontent.com/kubernetes/release/master/images/build/debian-hyperkube-base/OWNERS
   - name: kubernetes/repo-infra
     description: |
       Creates and maintains tools and templates for Kubernetes org repositories.